A look at language collocations and keywords. Lecture 3

Overview
The focus of this talk – the corpus linguistics perspective collocations and keywords
• Some examples
• Multi-methods

Frequency lists

Collocates of diamond

How large should the span be?
Typically set at +/- 5 words. This seems to be the most useful span for collocates
Similarly many people set a minimum threshold of frequency for words to count as collocates. I usually use a minimum frequency of 10
Option to stop at sentence boundaries

Collocates of company

Rank by frequency

Mutual information
количество взаимной информации

Dice coefficient
коэффициент Дайса

A look at language collocations and keywords

Colligation
A word collocates with a particular grammatical class.
E.g ‘he’ colligates with verbs
‘Mrs’ colligates with proper nouns
determiners colligate with nouns

Semantic preference
Similar to Bill Louw’s concept of semantic prosody.
‘the relation, not between individual words, but between a lemma or word-form and a set of semantically related words’ Stubbs (2001: 65)

Semantic preference – glass of
wine, sherry, champagne, beer, poured, water, juice, brandy, milk, whisky, orange, lemonade, rum, iced, sipped, gin, vodka, small, port, cider, lager

Discourse prosody

Discourse prosody

(Corpus) Keywords
A keyword list is calculated by comparing 2 frequency lists together – usually a much larger reference corpus against a smaller specialised corpus (but sometimes 2 equal sized corpora).
• Chi-square or log-likelihood test identify the words that are statistically much more frequent in one list when compared to the other.

http://ucrel.lancs.ac.uk/llwizard.html

When is a word a keyword?
The analyst needs to apply cut-off points for statistical significance.
• Some analysts only look at the top 10 or 50 or 100 keywords instead.
• Additionally, sometimes a minimum frequency is applied (e.g. a word must occur 20 times before it’s a keyword)
• Also, we may specify a keyword has to be reasonably well distributed (occurring in at least 20 texts)

Common types of keywords
1.Proper nouns (Clegg, Ghana etc)
2. Markers of style (often grammatical words like must, betwixt)
3. Spelling idiosyncrasies (color/colour)
4. “Aboutness” words (politics, recipe etc)

What’s the point of it?

Example – Change over time
(Baker 2011)

Identifying key terms

Examples

Words that are declining the most

Children

Multi Methods
Corpora can answer some questions very well, others not at all.
Corpora can integrate with other methods gainfully
Corpora can help mesh quantitative and qualitative analyses
Corpora are a tool – and like any tool they are good for some jobs and not others. They should also be part of a tool set.

Summing up
Collocates and keywords are important techniques in corpus linguistics – you will come across the terms many times on this course
They can tell us ‘about’ texts
They can tell us about change over time
They can help us decode argumentation strategies
And more besides!

GraphColl: Collocations in #LancsBox
Collocation is systematic co-occurrence of words in text and discourse that we identify statistically