Geminate consonants are phonemically contrastive in Biblical Hebrew. That is, phonetically they are consonants, but phonemically they behave as vowels. However, phonemically aspirated fricatives are rare. Dinka has a rich vowel system, with thirteen phonemically contrastive short vowels. The only common labiodental sounds to occur phonemically are the fricatives and the approximant. This is not phonetically tones although phonemically it can be analyzed as such. Maltese has seven falling diphthongs, though they may be considered VC sequences phonemically. Many languages do not distinguish vowel length phonemically. It includes phonemically distinctive implosive consonants, which are unusual among the Indo-European languages. Consonant length is no longer phonemically distinctive in most Romance languages. Nevertheless, semivowels may be phonemically equivalent with vowels. Hence, one speaks discriminatingly of "nasal" vowels (i.e. phonemically so) and "nasalized" vowels. Word stress is not phonemically contrastive in Standard Arabic. In that interpretation, Italian has only falling diphthongs (phonemically at least, cf. A few languages, perhaps 2%, contain no phonemically distinctive nasals.