Tillamook is an extinctSalishan language, formerly spoken by the Tillamook people in northwestern Oregon, United States. The last fluent speaker is believed to have died in the 1970s; between 1965 and 1972, in an effort to prevent the language from being lost, a group of researchers from the University of Hawaii interviewed the few remaining Tillamook-speakers and created a 120-page dictionary.
The so-called "rounded" consonants (traditionally marked with the diacritic ⟨ʷ⟩, but here indicated with ⟨ᵓ⟩), including rounded vowels and ⟨w⟩ (/ɰᵓ/), are not actually labialized. The acoustic effect of labialization is created entirely inside the mouth by cupping the tongue. Uvulars with this distinctive internal rounding have "a kind of ɔ timbre" while "rounded" front velars have ɯ coloring. These contrast and oppose otherwise very similar segments having ɛ or ɪ coloring—the "unrounded" consonants.
/w/ is also formed with this internal rounding instead of true labialization, making it akin to [ɰ]. So are vowel sounds formerly written as /o/ or /u/, which are best characterized as the diphthong /əɰ/ with increasing internal rounding.