Labiodental fricatives

Labiodental fricatives are produced by the lower lip being placed against the upper teeth so that friction is caused when the air pressure builds up. The labiodental sounds form a pair, /f/ and /v/, the first of which is Fortis, the latter Lenis. The fortis fricative is never voiced, and the lenis is commonly devoiced when not surrounded by other voiced sounds. This generally occurs in the end position of a word. The SBE lenis fricative /v/ is noticeably different from Norwegian /v/, as it carries much more friction than its Norwegian counterpart. Norwegians should take great care to observe the difference. The lenis fricative has a marked lengthening effect on the preceding sound(s).