Tsuruya is the hyperactive friend of Mikuru (from the current time plane), notable for her loud voice, knee-length hair and prominent tooth, who possesses a cheerful and friendly disposition. Her fang-like tooth gives her an idiosyncratic speech pattern, causing her to misspeak words by leaving out syllables. Her speech pattern is often accompanied with a lisp and catch phrases of "megas" and "nyoro". She was also named "honorary consultant of the SOS Brigade" by Haruhi.

She appears relatively sparingly throughout the anime.

Source:Wikipedia