Communication Accommodation Theory (CAT) and Linguistic Style Matching

Overview

Measure how a user converges toward community linguistic norms by comparing their function-word usage against community baselines via Linguistic Style Matching (LSM). The core principle: people unconsciously adjust their function-word usage to match the groups they engage with, and the degree of this adjustment -- measured as LSM -- reveals which communities exert the strongest stylistic pull on a user. Function words (pronouns, articles, prepositions, conjunctions, auxiliary verbs, adverbs, negations, quantifiers) are the signal because they reflect cognitive style rather than topic -- two people discussing completely different subjects will still converge on function-word usage if they are accommodating to each other.

Theoretical foundation: Communication Accommodation Theory (Giles, 1973; Giles & Ogay, 2007) predicts that individuals converge their communication style toward groups they identify with and diverge from groups they distance from. Linguistic Style Matching (Ireland et al., 2011; Gonzales, Hancock & Pennebaker, 2010) operationalizes this convergence through function-word similarity, using the formula developed by Pennebaker and colleagues. The key insight from Pennebaker's research is that function words are produced largely automatically and are resistant to conscious manipulation, making them a more reliable indicator of accommodation than content words.

LSM score range: Scores range from approximately 0.50 to 1.00, where higher values indicate greater stylistic convergence. An LSM of 1.00 means identical function-word distributions; 0.50 indicates near-random similarity. In practice, scores above 0.80 suggest strong accommodation, 0.65-0.80 moderate accommodation, and below 0.65 weak or no accommodation.

When to Use

• Quantifying how strongly a user adapts their writing style to different communities
• Ranking communities by the degree of linguistic accommodation a user exhibits
• Tracking whether a user's style converges toward or diverges from a community over time
• Identifying "linguistic home" communities where a user's style most closely matches norms
• Comparing accommodation patterns across multiple communities to find style-adoption targets
• Establishing function-word baselines for community writing norms
• Feeding accommodation scores into archetype or persona analysis