Grammar words, too, not just words like 'coffee', 'fit' and 'phwoar'. Told you it was worth knowing your grammar words.
As the article points out at the end: Is this convergence, or subconscious awareness of someone who 'speaks your language'?
The Language of Love: Word Usage Predicts Romantic Attraction
http://www.scientificamerican.com/article.cfm?id=the-language-of-love