Arabic definite article
A consonant may be long because of the form of the noun or verb; e.g., the causative form of the verb requires the second consonant of the root to be long, as in ' above, or by assimilation of consonants, for example the ' of the Arabic definite article "al-" assimilates to all dental consonants, e.g. () ' instead of ', or through metathesis, the switching of sounds, for example ' 'less, fewer' (instead of * '), as compared to "" 'greater'.