Lexical bundles (LB) testify to Sinclair's idiom principle (SIP), and measure formulaicity, complexity and (non-) creativity (FCN). We exploit the information-theoretic measure of surprisal to analyze these.Frequency as measure of LB has been criticized (McEnery et al, 2006:208–220), instead collocation measures were suggested until Biber (2009:286–290) raised three criticisms. First, MI ranks rare collocations, which often include idioms, highest. We answer that also idioms are formulaic, and there are collocation measures which have a bias towards frequent collocations.Second, MI doesn't respect word order. We thus use directed word transition probabilities like surprisal (Levy and Jaeger 2007):3-gram surprisal =Third, formulaic sequences are often discontinuous. We thus sum over sequences, use 3-grams as atoms, and address syntactic surprisal.We argue that abstracting to surprisal as measure of LB and FCN is appropriate, as it expresses reader expectations and text entropy. We use surprisal to analyse differences between:
- spoken and written learner language (L2);
- L2 across proficiency levels;
- L2 compared with L1
We test Pawley and Syder (1983)'s and Levy and Jaeger (2007)'s hypothesis that native speakers play the tug-of-war between formulaicity and expressiveness best, thus minimizing comprehension difficulty, according to the uniform information density principle.