Syntactic bootstrapping
Syntactic bootstrapping is a theory in developmental psycholinguistics and language acquisition which proposes that children learn word meanings by recognizing syntactic categories and the structure of their language. It is proposed that children have innate knowledge of the links between syntactic and semantic categories and can use these observations to make inferences about word meaning. Learning words in one's native language can be challenging because the extralinguistic context of use does not give specific enough information about word meanings. Therefore, in addition to extralinguistic cues, conclusions about syntactic categories are made which then lead to inferences about a word's meaning. This theory aims to explain the acquisition of lexical categories such as verbs, nouns, etc. and functional categories such as case markers, determiners, etc.
Basis of bootstrapping
The syntactic-semantic link
There are a number of hypotheses that attempt to explain how children acquire various aspects of language, such as syntax and word meanings. Even within the community of those who believe in bootstrapping, there are various hypotheses that attempt to explain how children acquire the same aspect of language. For example, under semantic bootstrapping, learning word meanings to understand the difference between physical objects, agents and actions is used to acquire the syntax of a language. However, prosodic bootstrapping also attempts to explain how children acquire the syntax of their language, but through prosodic cues. Finally, syntactic bootstrapping proposes that word meanings are acquired through knowledge of a language's syntactic structure.However, regardless of the method of acquisitions, there is a consensus among bootstrappers that bootstrapping theories of lexical acquisition depend on the natural link between semantic meaning and syntactic function. This syntactic-semantic link must be readily available for children to begin learning language and, therefore, must be innate. The link functions to map semantic concepts of objects, actions and attributes to syntactic categories of nouns, verbs and adjectives, respectively.
Underlying aspects
Diesendruck characterized these different mapping proposals as being on two dimensions: specificity to word learning and the source of support for word learning. For specificity to word learning, knowledge of lexical constraints is only useful for learning new words whereas attention to novelty is a characteristic of attention that applies beyond the domain of language. The latter dimension involves whether the source of support for word learning is endogenous or exogenous. For the word-learning task, the child brings their own conceptual understandings about the world, but their input comes from outside them.As mentioned above, the different theories of lexical acquisition are not mutually exclusive and do overlap each other. P. Bloom argued that there are three basic capacities that underlie child word learning: understanding mental states, understanding the kinds of things that get labeled, and understanding syntactic cues; these capacities correspond to social-cognitive understandings, cognitive biases and syntax, respectively. These underlying aspects of word learning may also change over time as the child develops. Older children have some syntax and word meanings acquired already so they may be less dependent on their input compared to children just beginning lexical development.
History
One of the earliest demonstrations of the existence of syntactic bootstrapping is an experiment done by Roger Brown at Harvard University in 1957. In his research, Brown demonstrated that preschool-aged children could use their knowledge of different parts of speech to distinguish the meaning of nonsense words in English. The results of Brown's experiment provided the first evidence showing that children could use syntax to infer meaning for newly encountered words and that they acquired grammar and semantics simultaneously. Brown's experiment was the beginning of the framework needed in order for the theory to thrive.This led developmental psycholinguists like Lila Gleitman, who coined the term syntactic bootstrapping in 1990, to argue that syntax was pivotal for language learning, as it also gives a learner clues about semantics. According to Gleitman's hypothesis, verbs are learned with a delay compared to other parts of speech because the linguistic information that supports their acquisition is not available during the early stages of language acquisition. The acquisition of verb meaning in children is pivotal to their language development. Syntactic bootstrapping seeks to explain how children acquire these words.
Logic and evidence
The syntactic bootstrapping hypothesis is based on the idea that there are universal/innate links between syntactic categories and semantic categories. Learners can therefore use their observations about the syntactic categories of novel words to make inferences about their meanings. This hypothesis is intended to solve the problem that the extralinguistic context is uninformative by itself to make conclusions about a novel word's meaning.For example, a child hears the sentence, “The cat meeped the bird.” If the child is familiar with the way arguments of verbs interact with the verb, he will infer that "the cat" is the agent and that "the bird" is the patient. Then, he can use these syntactic observations to infer that "meep" is a behaviour that the cat is doing to the bird.
Children's ability to identify syntactic categories may be supported by Prosodic bootstrapping. Prosodic bootstrapping is the hypothesis that children use prosodic cues, such as intonation and stress, to identify word boundaries.
Sensitivity to syntactic categories
Landau and Gleitman found when studying the acquisition of the verbs look and see by blind children that contextual clues appeared to be insufficient to explain their ability to differentiate these verbs . They considered the possibility that perceptual verbs might be used more by the blind child's mother when talking about nearby objects, since the child had to touch objects to perceive them. An analysis of the mother's utterances however, found this not to be the case.The solution investigated by Gleitman et al. was that syntactic categories, narrow down the contexts in which verbs are present, allowing children to learn their specific meanings in isolation. This narrowing provided evidence for their original hypothesis. When utterances that selected for perception verbs only were analyzed, the mother's use of the verbs look and see for nearby objects increased significantly. Gleitman concluded that a narrowing of contexts, then contextual support were required for the blind children to learn verbs.
By proxy, since there are many verbs that sighted children do not have direct experience with, they must use the same mechanism as well. In Gleitman's example, it is shown how direct experience is rarely present, as events are not labelled with their corresponding verb words. When a person returns home they say "Hi! How was your day?" as opposed to "I'm opening the door!"
Gleitman has this example to provide for the cases of the words /put/ and /look/: /put/ takes three noun entries in the example string "John put the ball on the table", as opposed to the two noun entries in "John looked at me." This distinction allows /put/ to be a candidate for a "transfer" type semantic description, as a "transfer" type verb must have a mover, destination, and object partaking in movement. Gleitman identifies the matching of these semantic types as the crux of context narrowing, and asserts that many other types exist, such as "perceptual," "mental," "cause," "symmetry," and "cognition."
Additionally, Waxman and Booth found that children who heard nouns focused on the object categories and children who focused on adjectives focused on an object's properties and categories. This shows that children are sensitive to different syntactic categories and can use their observations of syntax to infer word meaning.
Sensitivity to syntactic framing
In Roger Brown's 1957 experiment, children between the ages of three and five were shown various pictures depicting nonsense words that represented either singular nouns, mass nouns, count nouns or verbs. When the novel words were positioned in a question format, the children were able to use the placement of the novel word in the sentence to draw conclusions focus on different aspects of the image shown and adjusted their answer. For example, when Brown wanted the child to identify a mass noun, he would ask the children "do you see any sib", and the child would point at the pictured mass noun or noun indicating quantity.| Mass noun environment | Do you see any sib? |
| Verb environment | What is sibbing? |
| Singular noun environment | Do you see a sib? |
When children made guesses, they were correct more than half of the time. This shows that children are sensitive to the syntactic position of words, and can correctly associate a novel word with its syntactic category.
Harrigan, Hacquard, and Lidz —Found that children's interpretation of a new attitude verb depended on the syntactic frame in which it was introduced. In the experiment, children who heard the word 'hope' presented in the same syntactic frame as 'want' connected the new verb 'hope' with a meaning of desire. On the other hand, those that heard 'hope' presented in the same frame as 'think' made no such association between desire and the new verb, instead of associating the novel verb with belief. This provides evidence that children use syntax to some extent in learning the meaning behind these sorts of abstract verbs.
Papafragou, Cassidy, Gleitman —Participants were asked to identify verbs within the context of a video. Papafragou et al. had children watch 12 videotaped stories. 4 stories about the subject's desires and 8 stories that varied in the subject's beliefs and the framing of a novel verb. At the end of the tape, they would hear a sentence describing the scene but the sentence's verb was replaced with a novel word. Children were asked to respond with what they thought the word meant. Their responses were categorized 4 ways: Action, Belief, Desire, and Other. They found that action words were easily interpreted by children. However, false belief scenes with the complementizer phrase caused for children to respond with belief words more often. Results showed that participants in the experiment identified the verb most accurately when they could use both the video and sentence contexts. When it comes to attitude verbs, children are sensitive to the syntactic framing of the verb in question.
| Categories | Action | Belief | Desire | Other |
| Go, Take, Get, Make | Know, Think | Like, Want, Need | Be, Do |
Wellwood, Gagliardi, and Lidz — showed that four-year-olds can understand the difference between a quantitative or qualitative word, based on its syntactic position within a sentence. In “Gleebest of the cows are by the barn,” the novel word “gleebest” is in a determiner position, and is inferred to mean “most” or “many.” In “the gleebest cows are by the barn,” “gleebest” is in an adjective position, and children infer it to mean “spotty” or another quality. These results are significant because they show children using syntax to understand word meanings.
In the Gillette et al. study—, the researchers tested adults to see what difficulties they would face when asked to identify a word from a muted, videotaped scene. They found that adults had trouble identifying the word, especially verbs, when they could only refer to the scene. Their performance increased once they were given the syntactic context for the mystery word. These results indicate that word learning is aided by the presence of syntactic context.