science

Multiword expression

Multiword expression is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Multiword expression rather than just read about it. In short: A multiword expression (MWE), also called phraseme, is a lexeme-like unit made up of a sequence of two or more lexemes that has properties that are not predictable from the properties of the individual lexemes or their normal mode of combination. MWEs differ from lexemes in that the latter are required by many sources to have meaning that cannot be derived from the meaning of separate components.

Key takeaways

Multiword expression belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Multiword expression to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Multiword expression from memory before moving on to harder problems.

Reference excerpt

A multiword expression (MWE), also called phraseme, is a lexeme-like unit made up of a sequence of two or more lexemes that has properties that are not predictable from the properties of the individual lexemes or their normal mode of combination. MWEs differ from lexemes in that the latter are required by many sources to have meaning that cannot be derived from the meaning of separate components. While MWEs must have some properties that cannot be derived from the same property of the components, the property in question does not need to be meaning. For a shorter definition, MWEs can be described as "idiosyncratic interpretations that cross word boundaries (or spaces)". A multiword expression can be a compound, a fragment of a sentence, or a sentence. The group of lexemes which makup up a MWE can be continuous or discontinuous. It is not always possible to mark a MWE with a part of speech. A MWE may be more or less frozen. Example #1 in English: to kick the bucket, which means to die rather than to hit a bucket with one's foot. In this example, that is an endocentric compound, the part of speech may be determined as being a verb. The MWE is frozen, in the sense that no variation is possible. Example #2 in English: to throw <somebody> to the lions. The pattern <somebody> restricts the usage. The expression is half-frozen because a certain degree of variation is possible but not everything is possible. It is not possible, for instance, to say to the three lions. Like the previous example, the part of speech is a verb. Example #3 in French: la moutarde <me,te,lui,nous,vous,leur> monte au nez. This MWE is more frozen than the other examples. Let us add that a tense variation is allowed for the verb but we cannot determine what is the part of speech for the whole expression because it is a sentence.

Machine translation (MT) According to Sag et al. (2002), multiword expressions are, apart from disambiguation, one of the two key problems for natural language processing (NLP) and especially for machine translation (MT). The number of MWEs in a speaker's lexicon is estimated to be of the same order of magnitude as the number of single words. Specialized domain vocabulary overwhelmingly consists of MWEs, hence, the proportion of MWEs will rise as a system adds vocabulary for new domains, because each domain adds more MWEs than simplex words.

Problems The greatest problem for translating MWEs might be the idiomaticity problem, as many MWEs have an idiomatic sense, to a higher or a lesser degree. For example, it is hard to predict for a system that an expression like kick the bucket has a meaning that is totally unrelated to the meaning of kick, the and bucket while appearing to conform to the grammar of English Vps. Idioms cannot be translated literally, because in many cases the idiom does not exist in an equivalent form in the target language. Attention has to be paid to syntactic and semantic (non)equivalence. Also, not every MWE of the source language has a MWE in the target language as well. For example, the German MWE ins Auge fassen can only be translated by the English one-word term envisage.

Approaches The most promising approach to the challenge of translating MWEs is example based MT, because in this case each MWE can be listed as an example with its translation equivalent in the target language. For rule based MT it would be to difficult to define rules to translate MWEs, due to the magnitude of different kinds of MWEs. Nevertheless, an example based MT system has to apply different rules for the translation of continuous and discontinuous MWEs as it is harder to identify a discontinuous MWE in a sentence where words are inserted between the different components of one MWE.

See also Compound (linguistics) Lexical Markup Framework Light verb construction n-gram Phraseme

References

Dimitra Anastasiou: Idiom Treatment Experiments in Machine Translation (2010), Saarbrücken. Ivan A. Sag, Timothy Baldwin, Francis Bond, Ann Copestake and Dan Flickinger: Multiword Expressions: A Pain in the Neck for NLP (2002) in: LECTURE NOTES IN COMPUTER SCIENCE, Vol. 2276, pp. 1–15.

External links Multiword Expression Project, at Stanford University Workshops on Multiword Expressions Multiword Expressions in ACL Wiki Muller, Peter; Ohneiser, Ingeborg; Olsen, Susan; Rainer, Franz (Oct 2011). Word Formation, An International Handbook of the Languages of Europe (HSK Series) (PDF). Berlin: De Gruyter. p. Chapter 25: Multword Expressions. Archived (PDF) from the original on 2018-01-27. Retrieved 8 August 2018.{{cite book}}: CS1 maint: publisher location (link) Sag, Ivan A; Baldwin, Timothy; Bond, Francis; Copestake, Ann; Flickinger, Dan (2002). "Multiword Expressions: A Pain in the Neck for NLP". Computational Linguistics and Intelligent Text Processing. Lecture Notes in Computer Science. Vol. 2276. pp. 1–15. doi:10.1007/3-540-45715-1_1. hdl:10356/79581. ISBN 978-3-540-43219-7. Retrieved 8 August 2018. Sailer M, Markantonatou S (2018). Sailer M, Markantonatou S (eds.). Multiword expressions: Insights from a multi-lingual perspective (pdf). Berlin: Language Science Press. doi:10.5281/zenodo.1182583. ISBN 978-3-96110-063-7. Parmentier Y, Waszczuk J (2019). Parmentier Y, Waszczuk J (eds.). Representation and parsing of multiword expressions: Current trends (pdf). Berlin: Language Science Press. doi:10.5281/zenodo.2579017. ISBN 978-3-96110-145-0.

Worked examples

Example 1 — a first encounter with Multiword expression

Start with the simplest possible case. Write down what Multiword expression claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Multiword expression before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Multiword expression ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Multiword expression

In research: Multiword expression appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Multiword expression in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Multiword expression is common in secondary-school and first-year university syllabi. It links to neighbouring topics Lexicology, so understanding it makes those chapters shorter.
In everyday life: Look for Multiword expression outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Multiword expression in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Multiword expression means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Multiword expression out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Multiword expression in simple terms?

Why does Multiword expression matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Multiword expression?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Multiword expression.