/w/ is often included with the diphthongs rather than the consonants, as it only occurs in rising diphthongs and sequences of long vowel plus glide (see the Diphthongs section). However, since these are analysed and transcribed as consonants in this article, /w/ is included here as a consonant. /w/ contrasts with /v/ in for example the pair belove/bəˈloːvə/ - bliuwe/ˈbljoːwə/.
/m, p, b/ are bilabial, whereas /f, v/ are labiodental.
/v/ has two allophones: an approximant [ʋ], which appears word-initially, and a fricative [v], which occurs elsewhere.
West Frisian has final obstruent devoicing, meaning that voiced obstruents are merged with the voiceless ones at the end of a word. Thus, word-final /b, d, v, z, ɣ/ are merged into voiceless /p, t, f, s, x/, although final /b/ is rare. The spelling reflects this in the case of the fricatives, but not in the case of the plosives, which remain spelled with ⟨b⟩ and ⟨d⟩.
The long vowels are considerably longer than the short vowels. The former are generally over 250 ms, whereas the latter are generally under 150 ms.
Some speakers merge the long vowels /iː, uː/ with the centering diphthongs /iə̯, uə̯/.
/yː/ is infrequent. It and the other long close rounded vowel /uː/ are absent from the dialect of Leeuwarden.
/ø/ is phonetically central [ɵ] and is quite similar to /ə/. It can be treated as its stressed equivalent. In phonemic transcription, many scholars transcribe it with ⟨ø⟩, but ⟨ɵ⟩ and ⟨ʏ⟩ are occasionally also used.
Although they pattern with monophthongs, the long close-mid vowels transcribed /eː, øː, oː/ are often realized as narrow closing diphthongs [ei̯, øy̑, ou̯]. However, there are exceptions: for instance, speakers of the Hindeloopers dialect realize /øː/ as a long monophthong [øː].
Nearly all words with /øː/ are loanwords from Standard Dutch.
Frisian is traditionally analysed as having both falling and rising diphthongs. Booij (1989) argues that the rising diphthongs are in fact glide-vowel sequences, not real diphthongs. This view is supported by Hoekstra & Tiersma (2013) who transcribe them with with consonant symbols /jɪ, jɛ, wa, wo/, which is the convention used in this article.
Frisian also possesses sequences of a long vowel followed by a glide. According to Booij, the glide behaves as a consonant in these sequences, because it is shifted entirely to the next syllable when a following vowel is added. Visser also includes sequences of a high vowel plus glide among these. Such sequences are transcribed with a consonant symbol in this article, e.g.
aai/aːj/ ~ aaien/ˈaː.jən/
bliuw/bljoːw/ ~ bliuwen/ˈbljoː.wən/
moai/moːj/ ~ moaie/ˈmoː.jə/
iuw/iːw/ ~ iuwen/ˈiː.wən/
bloei/bluːj/ ~ bloeie/ˈbluː.jən/
In Southwestern dialects, the sequences /wa, wo/ are monophthongized to short central [ɞ, ɵ].
The closeness of either of the elements of /ɛi̯/ is somewhat variable, so that its phonetic realization is [æi̯ ~ æɪ̯ ~ ɛi̯ ~ ɛɪ̯].
The first element of /œy̑/ is more like [œ] than [ø]. Many scholars transcribe this sound as /øy̑/, Booij (1989) transcribes it as /ʌy̑/, yet this article transcribes it /œy̑/ to show that it is clearly distinct from the common diphthongal realization of /øː/ (having a much lower starting point) and that it is virtually identical to /œy̑/ in Standard Dutch.
Some scholars transcribe /ɔu̯/ as /ɔu̯/, yet others transcribe it as /au̯/. Phonetically, the first element of this diphthong may be either of these, i.e. [ɔ] or, less often, [a].
Hoekstra, Jarich (2001). "12. Standard West Frisian". In Munske, Horst Haider; Århammar, Hans (eds.). Handbook of Frisian studies. Tübingen: Max Niemeyer Verlag GmbH. pp. 83–98. ISBN3-484-73048-X. Retrieved 30 March 2017.
Hoekstra, Jarich; Tiersma, Peter Meijes (2013) [First published 1994]. "16 Frisian". In König, Ekkehard; van der Auwera, Johan (eds.). The Germanic Languages. Routledge. pp. 505–531. ISBN0-415-05768-X. Retrieved 30 March 2017.
Hof, Jan Jelles (1933). Friesche Dialectgeographie(PDF) (in Dutch). The Hague: Martinus Nijhoff. Archived(PDF) from the original on 7 October 2016. Retrieved 30 March 2017.
Keil, Benjamin (2003). "Frisian phonology"(PDF). Los Angeles: UCLA Department of Linguistics. Archived(PDF) from the original on 4 March 2016. Retrieved 30 March 2017.
Tiersma, Peter Meijes (1999) [First published 1985 in Dordrecht by Foris Publications]. Frisian Reference Grammar (2nd ed.). Leeuwarden: Fryske Akademy. ISBN90-6171-886-4.
van der Veen, Klaas F. (2001). "13. West Frisian Dialectology and Dialects". In Munske, Horst Haider; Århammar, Hans (eds.). Handbook of Frisian studies. Tübingen: Max Niemeyer Verlag GmbH. pp. 98–116. ISBN3-484-73048-X. Retrieved 30 March 2017.
Cohen, Antonie; Ebeling, Carl L.; Fokkema, Klaas; van Holk, André G.F. (1978) [First published 1961]. Fonologie van het Nederlands en het Fries: inleiding tot de moderne klankleer (in Dutch) (2nd ed.). The Hague: Martinus Nijhoff.
Fokkema, Klaas (1961). "Consonantgroepen in de Zuidwesthoek van Friesland". In Heeroma, Klaas Hanzen; Fokkema, Klaas (eds.). Structuurgeografie (in Dutch). Amsterdam: Noord-Hollandsche Uitg. Mij. pp. 16–26.