# Syntactic Phrase Structure ### Will Styler - LIGN 6 --- ### Today's Plan - Phrase Structure Rules - Structural Ambiguity --- ### Last time, we talked about constituents - Noun Phrases - Verb Phrases - Prepositional Phrases --- ### ... and we realized that the world of syntax isn't flat - (Neither is the rest of the world, damnit) --- ### Now, let's think a bit more about those structures --- # Phrase Structure Rules --- ### We have intuitions about what can be inside a noun phrase in English... - The big, strong rhinoceros - *The big, quickly rhinoceros - *The strong, charged rhinoceros --- ### A verb phrase has constraints in English - I hugged the small kitten - *I small hugged the kitten - *I hugged gently the kitten (???) --- ### And sentences definitely have rules in English - Sam sent Amanda to the store. - *Sent Sam Amanda to the store. - *Amanda Sam to the store sent. --- ### So, English has rules about how phrases are built - ... that sounds like a language model to me! --- ### Today, we'll talk about a *very* basic approach to modeling syntax --- ### Phrase Structure Rules - Rules that describe the sub-elements which can form a given syntactic constituent - ... and their ordering - **Syntax trees are built from phrase structure rules!** --- ### Phrase structure rule format - X → Y Z - S → NP VP - "A sentence is composed of an NP, followed by a VP" - <img class="r-stretch" src="diagrams/tree_snpvp.jpg" alt="treesnpvptex [S [NP ] [VP ] ]"> --- ### Phrase structure rules are like building blocks of sentences - We build sentences by building chunks using PS rules - Then combining them into the desired larger forms - <img class="r-stretch" src="img/tangrams.jpg" alt="tangrams.jpg The user wants a detailed description of an image containing tangram puzzles. I need to describe each puzzle individually, noting the shapes used (triangles, squares, parallelograms), their colors, and the label underneath. The layout is a grid: 3 columns and 3 rows. Row 1: - Left: Shark. Blue triangle body, green triangle tail fin, yellow square head, purple parallelogram snout, orange triangle dorsal fin, red triangle mouth area. Label: SHARK. - Middle: Bear. Green triangle ear/head, blue triangle body, orange triangle leg, red triangle foot, purple parallelogram leg, white triangle tail/foot? Wait, let's look closer. It looks like a bear walking right. Green triangle head/ear, blue square/triangle body, orange triangle leg, red triangle foot, purple parallelogram back leg, white triangle tail. Label: BEAR. - Right: Man on Horse. Yellow diamond (head), orange triangle neck, green triangle body, blue triangle horse body, purple parallelogram legs, red triangle tail, white triangle head of man? No, let's re-evaluate. It looks like a figure riding a horse. Yellow diamond is the rider's head. Orange triangle is the rider's body/neck. Green triangle is the horse's neck/back. Blue triangle is the horse's body. Purple parallelogram are legs. Red triangle tail. White triangle is the horse's head? Or maybe the rider's arm? Let's stick to describing shapes and colors. Label: MAN ON HORSE. Row 2: - Left: Camel. Red triangle hump, purple parallelogram neck, yellow square body, orange triangle leg, green triangle tail/leg, blue triangle front leg. Label: CAMEL. - Middle: House. Yellow square chimney, purple parallelogram roof left, blue triangle roof right, orange triangle floor left, green triangle floor right, red triangle window? Or door? It looks like a house with a slanted roof. Label: HOUSE. - Right: Rabbit. Purple parallelogram ear, yellow diamond head, orange triangle body, red triangle tail, white triangle foot, blue triangle leg, green triangle back leg. Label: RABBIT. Row 3: - Left: Sailboat. Green triangle sail, blue triangle sail, orange rectangle base (made of triangles?), yellow square hull center, purple parallelogram stern, red triangle bow? Wait, let's look at the bottom row left. It says SAILBOAT. Top is a green triangle. Below that a blue triangle. Base is an orange shape made of two triangles and a square? No, it looks like an orange trapezoid made of shapes. Let's describe the components: Green triangle (top sail), Blue triangle (main sail), Orange base (made of two triangles and a yellow square?), Purple parallelogram (stern), Red triangle (bow). Actually, looking closely at the bottom left: Top is a green triangle. Below it is a blue triangle. The base consists of an orange trapezoid shape made of two small triangles and a yellow square? No, let's look at the standard tangram set. - Standard set: 2 large triangles, 1 medium triangle, 2 small triangles, 1 square, 1 parallelogram. - Sailboat: Green triangle (top sail), Blue triangle (main sail). Base: Orange trapezoid (made of two small triangles and a yellow square? No, usually the base is the large triangles or medium. Let's just describe what I see). - Visible shapes for Sailboat: Large green triangle pointing up. Medium blue triangle below it. Base looks like an orange shape made of two small triangles and a yellow square? Wait, there is a red triangle at the front (right side of base) and purple parallelogram at the back (left side). Let's re-examine. - Actually, looking at the bottom left image labeled SAILBOAT: Top is a large green triangle. Below it is a medium blue triangle. The hull/base consists of an orange shape on the left (looks like two small triangles), a yellow square in the middle, and a red triangle on the right? No, let's look at the colors again. - Leftmost part of base: Orange shape (two small triangles?). Middle: Yellow square. Rightmost: Red triangle. Far right: Purple parallelogram. Wait, that's too many pieces. A tangram has 7 pieces. - Let's count for Sailboat: Green triangle (1), Blue triangle (2). Base: Orange shape (3), Yellow square (4), Red triangle (5), Purple parallelogram (6). Where is the 7th? Maybe the orange part is two triangles. Yes, likely two small orange triangles making a larger base section. - Let's look at the label SAILBOAT. It's under the boat. - Middle: Goose. Red triangle head/neck top, purple parallelogram neck, yellow square body, green triangle tail, blue triangle wing/body, orange triangle leg? No, let's trace it. - Top left: Red triangle (head). Below it: Purple parallelogram (neck). Below that: Yellow square (body). To the right of yellow square: Green triangle (tail/wing?). Below that: Blue triangle (wing/body). Bottom left: Orange triangle (leg/foot). Wait, let's look at the shape. It looks like a goose standing. - Head: Red triangle pointing up/left. Neck: Purple parallelogram going down/right. Body: Yellow square. Wing/Tail: Green triangle pointing right. Lower body/Wing: Blue triangle pointing left. Leg/Foot: Orange triangle at bottom left. Wait, that's 6 pieces. Where is the 7th? Maybe the blue part is two triangles? Or the green part? - Let's look closer at GOOSE. Top red triangle. Purple parallelogram neck. Yellow square body. Green triangle tail (pointing right). Blue triangle wing (pointing left/down). Orange triangle leg (bottom left). That's 6 pieces. Is there a small white triangle somewhere? Ah, looking very closely at the goose... under the yellow square, there might be another piece. Or maybe the blue shape is two triangles. Let's assume standard tangram rules but describe what is visible. - Actually, let's look at the GOOSE again. Top red triangle. Purple parallelogram neck. Yellow square body. Green triangle tail (right). Blue triangle wing (left/down). Orange triangle leg (bottom left). Wait, there is a small white triangle near the head? No. Maybe the blue shape is two triangles. Let's just describe the visible colors and shapes. - Right: Cat. White triangle ear/head top, red triangle face/neck, orange triangle body, yellow square body, green triangle tail/back leg, purple parallelogram back leg/tail? - Top left: White triangle (ear). Below it: Red triangle (head). Below that: Orange triangle (body). Right of orange: Yellow square. Below yellow: Green triangle (back leg/body). Bottom right: Purple parallelogram (tail/leg). Wait, let's count. 1 white, 2 red, 3 orange, 4 yellow, 5 green, 6 purple. Where is the 7th? Maybe the green part is two triangles. Or the orange part. - Let's look at the label CAT. It's under the cat. General Layout: - The image has a light blue/grey background with faint patterns (maybe clouds or just texture). - There are three vertical columns. - Each column has three images stacked vertically. - Text is in black, uppercase, sans-serif font below each shape. Refining the descriptions for accuracy: 1. Shark: Top left. Blue triangle body. Green triangle tail fin (bottom right). Yellow square head. Purple parallelogram snout (top right). Orange triangle dorsal fin (top right corner). Red triangle mouth area (bottom left of blue body). Wait, let's look at the colors again. - Body: Large blue triangle. - Tail: Green triangle attached to bottom right. - Head: Yellow square attached to top right of blue triangle? No, looks like a yellow square is the head. - Snout: Purple parallelogram extending from the yellow square. - Dorsal fin: Orange triangle on top. - Mouth/Underbelly: Red triangle at bottom left. - Actually, let's look at the standard Shark tangram. Usually: Large blue triangle body. Small red triangle mouth. Medium green triangle tail. Yellow square head. Purple parallelogram snout. Orange triangle dorsal fin. White triangle? No white in this one. Wait, looking at the shark again... - Top left shape: Blue large triangle. - Bottom left of it: Red small triangle. - Right side attached to blue: Green medium triangle (tail). - Top right of green: Yellow square (head). - Attached to yellow: Purple parallelogram (snout). - On top of purple/blue junction: Orange triangle (fin). - Wait, there is a white triangle in the shark? Looking at the very top left... no. Looking near the tail... ah, there is a small white triangle between the green and blue? Or maybe part of the fin assembly. Let's look really closely at crop 1. - Crop 1 shows the Shark clearly. - Blue large triangle (body). - Red small triangle (mouth/bottom left). - Green medium triangle (tail, attached to right side of blue). - Yellow square (head, attached to top right of green? No, attached to top right of blue?). It looks like the yellow square is next to the purple parallelogram. - Purple parallelogram (snout, extending right from yellow square). - Orange triangle (dorsal fin, on top of the junction between blue and purple/yellow). - Wait, there is a white triangle! Look at the top left of the shark body. There is a small white triangle pointing up/left. It's attached to the blue triangle. So: Blue large triangle body. White small triangle dorsal fin? No, orange is on top. Maybe white is part of the tail? - Let's re-examine Shark based on standard tangram sets. Usually 2 large triangles (blue/green?), 1 medium (orange?), 2 small (red/white?), 1 square (yellow), 1 parallelogram (purple). - In this image: - Blue shape is a large triangle. - Green shape is a medium triangle? Or large? Looks like a medium triangle. - Yellow is a square. - Purple is a parallelogram. - Orange is a small triangle (dorsal fin). - Red is a small triangle (mouth). - White is a small triangle (tail fin tip?). It's located between the green and blue triangles, pointing up. 2. Bear: Top middle. - Green large triangle (head/ear). - Blue medium triangle (body). - Orange small triangle (leg). - Red small triangle (foot). - Purple parallelogram (back leg/body). - White small triangle (tail/foot?). It's at the bottom left. 3. Man on Horse: Top right. - Yellow diamond (rider head). - Orange triangle (rider body/neck). - Green triangle (horse neck/back). - Blue large triangle (horse body). - Purple parallelogram (horse legs). - Red small triangle (tail). - White small triangle (horse head?). It's on the far right. 4. Camel: Middle left. - Red small triangle (hump top). - Purple parallelogram (neck). - Yellow square (body). - Orange medium/large triangle (leg/body). - Green large triangle (tail/leg). - Blue medium triangle (front leg). - Wait, let's look closer. - Top: Red small triangle. - Below it: Purple parallelogram going down-right. - Right of purple: Yellow square. - Below yellow: Orange shape (looks like two triangles? No, one medium triangle). - Right of orange: Green large triangle. - Left of green/orange junction: Blue medium triangle. - This is getting complicated to parse perfectly without touching. I will describe the visual arrangement of colors and shapes as best as possible. 5. House: Middle center. - Yellow square (chimney). - Purple parallelogram (roof left slope). - Blue large triangle (roof right slope). - Orange medium triangle (floor/wall left). - Green large triangle (floor/wall right). - Red small triangle (window/door?). It's inside the orange/green area. 6. Rabbit: Middle right. - Purple parallelogram (long ear, pointing up-left). - Yellow diamond/square rotated (head). - Orange medium triangle (body). - Red small triangle (tail, top right). - White small triangle (foot, bottom left of body). - Blue medium triangle (leg/body). - Green large triangle (back leg/tail base). 7. Sailboat: Bottom left. - Green large triangle (top sail). - Blue medium triangle (main sail). - Base: Orange shape (two small triangles making a trapezoid?). Yellow square (center of hull). Red small triangle (bow/front). Purple parallelogram (stern/back). 8. Goose: Bottom center. - Red small triangle (head, top left). - Purple parallelogram (neck, going down-right). - Yellow square (body). - Green large triangle (tail/wing, pointing right). - Blue medium triangle (wing/body, pointing left/down). - Orange small triangle (leg/foot, bottom left). - Wait, where is the 7th piece? Maybe the blue part is two triangles. Or maybe there's a white piece hidden. Looking closely at the goose... under the yellow square, near the orange leg, there might be another shape. Actually, looking at the very top of the goose neck, there is a red triangle. Below that purple parallelogram. Then yellow square. To the right green triangle. Below green/blue junction... wait. - Let's look at the Goose again. - Top: Red small triangle (head). - Neck: Purple parallelogram. - Body: Yellow square. - Tail/Wing Right: Green large triangle. - Wing Left/Body Bottom: Blue medium triangle. - Leg/Foot: Orange small triangle. - Is there a white piece? Maybe the blue shape is actually two triangles (medium and small)? Or maybe the green one. I will describe it as a goose formed by red, purple, yellow, green, blue, and orange shapes. 9. Cat: Bottom right. - White small triangle (ear, top left). - Red small triangle (face/neck). - Orange medium triangle (body upper). - Yellow square (body lower). - Green large triangle (back leg/tail base). - Purple parallelogram (tail/back leg). - Wait, let's look at the cat again. - Top left: White small triangle (ear). - Below it: Red small triangle (head). - Right of red: Orange medium triangle (body). - Below orange: Yellow square. - Below yellow: Green large triangle (back leg/body). - Right of green: Purple parallelogram (tail/leg). - This seems to account for most pieces. Text: - SHARK, BEAR, MAN ON HORSE (Row 1) - CAMEL, HOUSE, RABBIT (Row 2) - SAILBOAT, GOOSE, CAT (Row 3) Background: - Light blue/grey with a subtle pattern. The right column has a slightly different background color, more beige/cream compared to the blue of the left and middle columns? No, looking closely, the whole image seems to have a light blue background, but the rightmost column (Man on Horse, Rabbit, Cat) is on a slightly lighter, possibly beige or off-white vertical strip. Wait, let's look at the full image. - The image is divided into three vertical panels. - Left panel: Blueish background. Contains Shark, Camel, Sailboat. - Middle panel: Lighter blue/grey background. Contains Bear, House, Goose. - Right panel: This description was generated automatically. Please feel free to ask questions if you have further questions about the nature of the image or its meaning within the presentation."> --- # How do we build trees? --- ## Building a phrase structure tree - Step 1: Find constituents and think about what *kinds* of phrases they are - "Huh, this is a preposition. There's gotta be a PP around here..." - Step 2: Start stitching constituents together according to our PS rules - Step 3: Check to make sure every branching obeys the phrase structure rules - "OK, this is Rule 9, now rule 1 to 2, then here's 11..." - Step 4: A beautiful tree will grow! --- # A Small Phrase Structure Grammar for English --- ## Noun Phrase Rules --- ### Rule 1) NP -> DET N' ### Rule 3) N' -> N <img class="r-stretch" src="diagrams/tree_rule1.jpg" alt="treerule1tex [NP [DET ] [N' ] ]"> <img class="r-stretch" src="diagrams/tree_rule3.jpg" alt="treerule3tex [N' [N ] ]"> --- ### Rule 1) NP -> DET N' ### Rule 3) N' -> N <img class="r-stretch" src="diagrams/tree_rule1_3.jpg" alt="treerule13tex [NP [DET the ] [N' [N cat ] ] ]"> --- ... but what if there's no determiner? --- ### Rule 2) NP -> N' ### Rule 3) N' -> N <img class="r-stretch" src="diagrams/tree_rule2.jpg" alt="treerule2tex [NP [N' ] ]"> <img class="r-stretch" src="diagrams/tree_rule3.jpg" alt="treerule3tex [N' [N ] ]"> --- ### Rule 2) NP -> N' ### Rule 3) N' -> N <img class="r-stretch" src="diagrams/tree_rule2_3.jpg" alt="treerule23tex [NP [N' [N Will Styler ] ] ]"> <img class="r-stretch" src="diagrams/tree_rule2_3_alt.jpg" alt="treerule23alttex [NP [N' [N Penguins ] ] ]"> --- ### How do we deal with adjectives? --- ### Rule 4) N' -> ADJ N' - We can combine Rule 1, Rule 4, and Rule 3... <img class="r-stretch" src="diagrams/tree_rule1.jpg" alt="treerule1tex [NP [DET ] [N' ] ]"> <img class="r-stretch" src="diagrams/tree_rule3.jpg" alt="treerule3tex [N' [N ] ]"> <img class="r-stretch" src="diagrams/tree_rule4.jpg" alt="treerule4tex [N' [ADJ ] [N' ] ]"> --- ### Rules 1, 3, 4 We can combine Rule 1, Rule 4, and Rule 3... <img class="r-stretch" src="diagrams/tree_rule1_3_4.jpg" alt="treerule134tex [NP [DET the ] [N' [ADJ cute ] [N' [N cat ] ] ] ]"> --- ### Rules 1, 3, 4 We can combine Rule 1, Rule 4, and Rule 3... <img class="r-stretch" src="diagrams/tree_rule1_3_4_alt.jpg" alt="treerule134alttex [NP [DET some ] [N' [ADJ angry ] [N' [N koalas ] ] ] ]"> --- ### ... Rule 4 is recursive! - The N' contains another N'! - It can apply as many times as you need! --- <img class="r-stretch" src="humorimg/hulkhoganfractal.jpg" alt="hulkhoganfractal.jpg The image features a muscular individual standing outdoors with a desert-like background that includes distant hills and sparse vegetation. The person is wearing a sleeveless black shirt with text on it, which appears to include the word Artist in green letters within a triangular design. They have long white hair styled in two braids, one on each side of their head, and are wearing a black bandana or headband around their forehead. The individual has a prominent mustache that is also white, matching the hair color. Their facial expression appears friendly and approachable, with a slight smile showing teeth. The person's arms are slightly bent at the elbows, suggesting they might be in a relaxed stance. The lighting suggests it could be daytime, possibly late afternoon given the softness of the light. The background is mostly barren earth tones, with muted greens and browns dominating the landscape. There are no other people or significant objects visible in the image besides the individual described. This description was generated automatically from image files by a local LLM, and thus, may not be fully accurate. Please feel free to ask questions if you have further questions about the nature of the image or its meaning within the presentation."> --- <img class="r-stretch" src="diagrams/tree_rule1_3_4.jpg" alt="treerule134tex [NP [DET the ] [N' [ADJ cute ] [N' [N cat ] ] ] ]"> --- <img class="r-stretch" src="diagrams/tree_rule4recursive.jpg" alt="treerule4recursivetex [NP [DET the ] [N' [ADJ cute ] [N' [ADJ black ] [N' [N cat ] ] ] ] ]"> --- <img class="r-stretch" src="diagrams/tree_rule4recursive2.jpg" alt="treerule4recursive2tex [NP [DET the ] [N' [ADJ tiny ] [N' [ADJ cute ] [N' [ADJ black ] [N' [N cat ] ] ] ] ] ]"> --- <img class="r-stretch" src="diagrams/tree_rule4recursive3.jpg" alt="treerule4recursive3tex [NP [DET the ] [N' [ADJ little ] [N' [ADJ tiny ] [N' [ADJ cute ] [N' [ADJ black ] [N' [N cat ] ] ] ] ] ] ]"> --- <img class="r-stretch" src="diagrams/tree_rule4recursive4.jpg" alt="treerule4recursive4tex [NP [DET the ] [N' [ADJ little ] [N' [ADJ tiny ] [N' [ADJ cute ] [N' [ADJ black ] [N' [ADJ stray ] [N' [N cat ] ] ] ] ] ] ] ]"> --- (... and so on) --- ## What about prepositions? Linguists love prepositions! --- ## Rule 5: NP -> NP PP ## Rule 6: PP -> P NP <img class="r-stretch" src="diagrams/tree_rule6.jpg" alt="treerule6tex [NP [NP ] [PP ] ]"> <img class="r-stretch" src="diagrams/tree_rule8.jpg" alt="treerule8tex [PP [P ] [NP ] ]"> --- ### Rules 5 and 6 <img class="r-stretch" src="diagrams/tree_rule6_8.jpg" alt="treerule68tex [NP [NP [DET the ] [N' [N dog ] ] ] [PP [P from ] [NP [DET the ] [N' [N future ] ] ] ] ]"> --- ### "Two computational linguists from San Diego" <img class="r-stretch" src="diagrams/tree_compling.jpg" alt="treecomplingtex [NP [NP [DET Two ] [N' [ADJ computational ] [N' [N linguists ] ] ] ] [PP [P from ] [NP [N' [N San Diego ] ] ] ] ]"> --- ## Now, let's make a sentence! --- ### Rule 7: S -> NP VP ### Rule 8: VP -> V <img class="r-stretch" src="diagrams/tree_rule9.jpg" alt="treerule9tex [S [NP ] [VP ] ]"> <img class="r-stretch" src="diagrams/tree_rule10.jpg" alt="treerule10tex [VP [V ] ]"> --- ### A very simple sentence <img class="r-stretch" src="diagrams/tree_rule2_3_9_10.jpg" alt="treerule23910tex [S [NP [N' [N Will ] ] ] [VP [V ate ] ] ]"> --- ### Adding in a preposition (with Rule 10) <img class="r-stretch" src="diagrams/tree_rule2_3_9_11_4_expanded_more_small.jpg" alt="treerule239114expandedmoresmalltex [S [NP [N' [N Will ] ] ] [VP [VP [V ate ] ] [PP [P with ] [NP [DET his ] [N' [N wife ] ] ] ] ] ]"> --- ### But lots of verbs are *transitive*, and take a noun phrase as the object (Rule 9) <img class="r-stretch" src="diagrams/tree_rule2_3_9_11.jpg" alt="treerule23911tex [S [NP [N' [N Will ] ] ] [VP [V ate ] [NP [DET the ] [N' [N cake ] ] ] ] ]"> --- ### ... and we can bring old rules back in! <img class="r-stretch" src="diagrams/tree_rule2_3_9_11_4.jpg" alt="treerule239114tex [S [NP [N' [N Will ] ] ] [VP [V ate ] [NP [DET the ] [N' [ADJ massive ] [N' [ADJ chocolate ] [N' [N cake ] ] ] ] ] ] ]"> --- ### ... and we can bring more old rules back in! <img class="r-stretch" src="diagrams/tree_rule2_3_9_11_4_expanded.jpg" alt="treerule239114expandedtex [S [NP [N' [N Will ] ] ] [VP [V ate ] [NP [NP [DET the ] [N' [ADJ massive ] [N' [ADJ chocolate ] [N' [N cake ] ] ] ] ] [PP [P from ] [NP [DET the ] [N' [ADJ new ] [N' [N bakery ] ] ] ] ] ] ] ]"> --- ### ... and we can add on another PP <img class="r-stretch" src="diagrams/tree_rule2_3_9_11_4_expanded_more.jpg" alt="treerule239114expandedmoretex [S [NP [N' [N Will ] ] ] [VP [VP [V ate ] [NP [NP [DET the ] [N' [ADJ massive ] [N' [ADJ chocolate ] [N' [N cake ] ] ] ] ] [PP [P from ] [NP [DET the ] [N' [ADJ new ] [N' [N bakery ] ] ] ] ] ] ] [PP [P with ] [NP [DET his ] [N' [N wife ] ] ] ] ] ]"> --- ### Is this starting to feel familiar? <img class="r-stretch" src="img/legos.jpg" alt="legos.jpg The image displays a large, disorganized pile of colorful plastic building blocks set against a stark white background. The bricks are primarily rectangular in shape and come in various standard sizes, ranging from small 1x2 or 2x2 squares to longer strips like 1x4 or 1x6 pieces. The colors are vibrant and varied. There is a significant amount of primary colors: bright red, deep blue, and sunny yellow. These are mixed with green bricks in various shades, stark black bricks, and clean white bricks. A few orange pieces are also visible within the mix. Each brick features the characteristic design of interlocking plastic blocks. The top surfaces are covered in raised circular studs or knobs, which allow the bricks to connect together. The sides of the bricks are smooth vertical walls with faint horizontal lines indicating where the internal structure connects to the bottom plate. The pile is heaped in the center of the frame. It looks like a bin of loose parts ready for building. - Near the top peak of the pile, there is a long red brick lying somewhat horizontally, next to a white piece and some green bricks. - On the left side of the pile, you can see a black brick with its studs facing upward, surrounded by blue and yellow pieces. A large white brick is tilted near the front left edge. - On the right side, there is a long yellow brick lying flat, angled slightly downward. Below it are several green and red bricks. - In the foreground at the bottom, the pile spreads out. There are small 1x2 bricks in blue, yellow, and red scattered near the base. A black brick lies flat near the front center. The lighting is bright and even, creating soft shadows within the crevices of the pile, which helps define the three-dimensional shape of the heap. There is no text or other objects in the image. This description was generated automatically. Please feel free to ask questions if you have further questions about the nature of the image or its meaning within the presentation."> --- ### Making Syntax Trees is combining small elements to make bigger, fancier trees <img class="r-stretch" src="diagrams/tree_dogs_long.jpg" alt="treedogslongtex [S [NP [N' [N I ] ] ] [VP [V saw ] [NP [NP [NP [DET the ] [N' [ADJ big ] [N' [ADJ sweet ] [N' [N dogs ] ] ] ] ] [PP [P from ] [NP [N' [N La Jolla ] ] ] ] ] [PP [P with ] [NP [N' [N fleas ] ] ] ] ] ] ]"> --- <img class="r-stretch" src="humorimg/deeper.jpg" alt="deeper.jpg The image shows two men engaged in a conversation. The man on the left is wearing a dark suit with a white shirt and has short brown hair. He appears to be speaking earnestly. The text overlaying this part of the image reads WE NEED TO GO at the top and DEEPER at the bottom, suggesting that they are discussing something serious or intense. The man on the right is also dressed in a dark suit with a white shirt but has short brown hair as well. He seems to be listening intently while looking towards his companion. The background of the image appears to be an interior setting, possibly an office or a formal room, given the presence of what looks like a glass table and some blurred objects that could be furniture. The overall tone of the image conveys a sense of urgency or importance in their discussion. This description was generated automatically from image files by a local LLM, and thus, may not be fully accurate. Please feel free to ask questions if you have further questions about the nature of the image or its meaning within the presentation."> --- ### Complementizers put sentences within sentences - Words like "that", "when", "if", "while", "as", and more --- <img class="r-stretch" src="diagrams/tree_complementizer1.jpg" alt="treecomplementizer1tex [S [NP [N' [N I ] ] ] [VP [V love ] [CP [C when ] [S [NP [N' [N you ] ] ] [VP [V hug ] [NP [N' [N squirrels ] ] ] ] ] ] ] ]"> --- ### ... we can go deeper <img class="r-stretch" src="diagrams/tree_complementizer2.jpg" alt="treecomplementizer2tex [S [NP [N' [N John ] ] ] [VP [V knows ] [CP [C that ] [S [NP [N' [N I ] ] ] [VP [V love ] [CP [C when ] [S [NP [N' [N you ] ] ] [VP [V hug ] [NP [N' [N squirrels ] ] ] ] ] ] ] ] ] ] ]"> --- ### ... and this combines with everything we've been doing ... <img class="r-stretch" src="diagrams/tree_complementizercake.jpg" alt="treecomplementizercaketex [S [NP [N' [N People ] ] ] [VP [V cheered ] [CP [C as ] [S [NP [N' [N Will ] ] ] [VP [VP [V ate ] [NP [NP [DET the ] [N' [ADJ massive ] [N' [ADJ chocolate ] [N' [N cake ] ] ] ] ] [PP [P from ] [NP [DET the ] [N' [ADJ new ] [N' [N bakery ] ] ] ] ] ] ] [PP [P with ] [NP [DET his ] [N' [N wife ] ] ] ] ] ] ] ] ]"> --- ### ... and just keeps getting worse ... <img class="r-stretch" src="diagrams/tree_complementizercake2.jpg" alt="treecomplementizercake2tex [S [NP [NP [DET The ] [N' [ADJ proud ] [N' [N baker ] ] ] ] [PP [P from ] [NP [N' [N San Bernadino ] ] ] ] ] [VP [V loved ] [CP [C that ] [S [NP [N' [N people ] ] ] [VP [V cheered ] [CP [C as ] [S [NP [N' [N Will ] ] ] [VP [VP [V ate ] [NP [NP [DET the ] [N' [ADJ massive ] [N' [ADJ chocolate ] [N' [N cake ] ] ] ] ] [PP [P from ] [NP [DET the ] [N' [ADJ new ] [N' [N bakery ] ] ] ] ] ] ] [PP [P with ] [NP [DET his ] [N' [N wife ] ] ] ] ] ] ] ] ] ] ] ]"> --- ## So that's how trees are grown --- ### In NLP, trees are usually stored with nested parentheses (S (NP (NP (DET The) (N' (ADJ proud) (N' (N baker)))) (PP (P from) (NP (N' (N San Bernadino))))) (VP (V loved) (CP (C that) (S (NP (N' (N people))) (VP (V cheered) (CP (C as) (S (NP (N' (N Will))) (VP (VP (V ate) (NP (NP (DET the) (N' (ADJ massive) (N' (ADJ chocolate) (N' (N cake))))) (PP (P from)(NP (DET the) (N' (ADJ new) (N' (N bakery)))))))(PP (P with) (NP (DET his) (N' (N wife)))))))))))) <img class="r-stretch" src="diagrams/tree_complementizercake2.jpg" alt="treecomplementizercake2tex [S [NP [NP [DET The ] [N' [ADJ proud ] [N' [N baker ] ] ] ] [PP [P from ] [NP [N' [N San Bernadino ] ] ] ] ] [VP [V loved ] [CP [C that ] [S [NP [N' [N people ] ] ] [VP [V cheered ] [CP [C as ] [S [NP [N' [N Will ] ] ] [VP [VP [V ate ] [NP [NP [DET the ] [N' [ADJ massive ] [N' [ADJ chocolate ] [N' [N cake ] ] ] ] ] [PP [P from ] [NP [DET the ] [N' [ADJ new ] [N' [N bakery ] ] ] ] ] ] ] [PP [P with ] [NP [DET his ] [N' [N wife ] ] ] ] ] ] ] ] ] ] ] ]"> --- ### We can use these trees to understand the structure of sentences! - Things that can be 'broken off the tree' cleanly are constituents - The constituency structure helps us understand the sentence better - ... because sometimes, it's ambiguous! --- # Structural Ambiguity --- ### Different structures can imply different meanings - The same written sentence can be treed in many different ways --- ### I [saw the man] [with the telescope] <img class="r-stretch" src="diagrams/tree_manwithtelescope1.jpg" alt="treemanwithtelescope1tex [S [NP I ] [VP [VP [V saw ] [NP [DET the ] [N' [N man ] ] ] ] [PP [P with ] [NP [DET the ] [N' [N telescope ] ] ] ] ] ]"> --- ### I saw [the man with the telescope] <img class="r-stretch" src="diagrams/tree_manwithtelescope2.jpg" alt="treemanwithtelescope2tex [S [NP I ] [VP [V saw ] [NP [NP [DET the ] [N' [N man ] ] ] [PP [P with ] [NP [DET the ] [N' [N telescope ] ] ] ] ] ] ]"> --- ### John slapped his friend with the smelly fish <img class="r-stretch" src="diagrams/tree_slappedwithfish1.jpg" alt="treeslappedwithfish1tex [S [NP [N' [N John ] ] ] [VP [V slapped ] [NP [NP [DET his ] [N' [N friend ] ] ] [PP [P with ] [NP [DET the ] [N' [ADJ smelly ] [N' [N fish ] ] ] ] ] ] ] ]"> --- ### John slapped his friend with the smelly fish <img class="r-stretch" src="diagrams/tree_slappedwithfish2.jpg" alt="treeslappedwithfish2tex [S [NP [N' [N John ] ] ] [VP [VP [V slapped ] [NP [DET his ] [N' [N friend ] ] ] ] [PP [P with ] [NP [DET the ] [N' [ADJ smelly ] [N' [N fish ] ] ] ] ] ] ]"> --- ### We as humans understand what structures are *plausible* --- <img class="r-stretch" src="diagrams/tree_dogs_long.jpg" alt="treedogslongtex [S [NP [N' [N I ] ] ] [VP [V saw ] [NP [NP [NP [DET the ] [N' [ADJ big ] [N' [ADJ sweet ] [N' [N dogs ] ] ] ] ] [PP [P from ] [NP [N' [N La Jolla ] ] ] ] ] [PP [P with ] [NP [N' [N fleas ] ] ] ] ] ] ]"> - This reads as expected --- <img class="r-stretch" src="diagrams/tree_dogs_long_wrong2.jpg" alt="treedogslongwrong2tex [S [NP [N' [N I ] ] ] [VP [VP [V saw ] [NP [NP [DET the ] [N' [ADJ big ] [N' [ADJ sweet ] [N' [N dogs ] ] ] ] ] [PP [P from ] [NP [N' [N La Jolla ] ] ] ] ] ] [PP [P with ] [NP [N' [N fleas ] ] ] ] ] ]"> - "I used a flea-based telescope" --- <img class="r-stretch" src="diagrams/tree_dogs_long_wrong.jpg" alt="treedogslongwrongtex [S [NP [N' [N I ] ] ] [VP [V saw ] [NP [NP [DET the ] [N' [ADJ big ] [N' [ADJ sweet ] [N' [N dogs ] ] ] ] ] [PP [P from ] [NP [NP [N' [N La Jolla ] ] ] [PP [P with ] [NP [N' [N fleas ] ] ] ] ] ] ] ] ]"> - "I'm from La Jolla with Fleas, not La Jolla" --- <img class="r-stretch" src="diagrams/tree_queenenglandshat1.jpg" alt="treequeenenglandshat1tex [S [NP I ] [VP [V saw ] [NP [DET [NP [DET the ] [NP [NP [N' [N Queen ] ] ] [PP [P of ] [NP [N' [N England ] ] ] ] ] ] [POSS 's ] ] [N' [N Hat ] ] ] ] ]"> - "I saw the hat of the Queen of England" --- <img class="r-stretch" src="diagrams/tree_queenenglandshat2.jpg" alt="treequeenenglandshat2tex [S [NP I ] [VP [V saw ] [NP [DET the ] [NP [NP [N' [N Queen ] ] ] [PP [P of ] [NP [DET [NP [N' [N England ] ] ] [POSS 's ] ] [N' [N Hat ] ] ] ] ] ] ] ]"> - "I saw the woman who is Queen of England's hat" --- ### We need to account for this in NLP! - Because the 'correct' parse isn't always obvious! - And we're not even always sure what the correct parts of speech are! --- ### You may think... <img class="r-stretch" src="diagrams/tree_phrasestructurerules.jpg" alt="treephrasestructurerulestex [NP [N' [ADJ Syntactic ] [N' [ADJ phrase structure ] [N' [N rules ] ] ] ] ]"> --- ### ... but in reality ... <img class="r-stretch" src="diagrams/tree_phrasestructurerules_alt.jpg" alt="treephrasestructurerulesalttex [S [NP [N' [ADJ Syntactic ] [N' [N phrase structure ] ] ] ] [VP [V rules! ] ] ]"> --- ### Correct parts of speech are crucial - ... and errors there tend to lead to errors in parsing! - So let's figure out how to get that right first! --- ### For Next Time - We'll talk about automatic POS tagging --- <huge>Thank you!</huge>