an unrounded back vowel). If a verb ends in t, it may change into d (especially gitmek and etmek). If a verb ends in open vowels (a or e), the open vowels become closed while adding -yor (because of the closed auxiliary vowel -i-). a becomes ı if the preceding vowel is unrounded, u if it is rounded (ağla -> ağlıyor, topla -> topluyor) e becomes i if the preceding vowel is unrounded, ü if it is rounded (bekle -> bekliyor, söyle -> söylüyor) If the verb ends in a consonant, the auxiliary vowel -i- must be added before -yor. It becomes -ı-, -u- or -ü- depending on the frontness and roundedness of the preceding vowel, because of the vowel harmony: -i if the preceding vowel is e or i (front unrounded): gel -> geliyor -ı if the preceding vowel is a or ı (back unrounded): bak -> bakıyor -u if the preceding vowel is o or u (back rounded): kork -> korkuyor -ü if the preceding vowel is ö or ü (front rounded): gör -> görüyor r of -yor may be dropped in colloquial speech. To form the negative of the past continuous tense, the negation suffix "-ma/-me", which becomes -mi, -mı, -mu, or -mü because of the closed auxiliary vowel and the vowel harmony, must be added before -yor. Examples: The epenthetic consonant y is inserted between -mu and -du. As -mu and -du (which have a rounded back vowel) succeeds -lar (which has an unrounded back vowel) instead of -yor (which has a rounded back vowel) when the subject is the third person plural, onlar, they become -mı and -dı (which have an unrounded back vowel). Semitic languages Semitic languages, especially the ancient forms, do not make use of the imperfect (or perfect) tense with verbs. Instead, they use the imperfective and perfective aspects, respectively. Aspects are similar to tenses, but differ by requiring contextual comprehension to know whether the verb indicates a completed or non-completed action. Dravidian languages Malayalam In Malayalam (verbs are never conjugated for grammatical person, which is indicated by a pronoun), there are two indicative imperfects, corresponding exactly with English: 1 -ഉകയായിരുന്നു (ukayāyirunnu) endings (... was...), for example: ഓടുകയായിരുന്നു (ōṭukayāyirunnu) ... was running 2 -ഉമായിരുന്നു (umāyirunnu) endings (... used to ...), for example: ഓടുമായിരുന്നു (ōṭumāyirunnu) ... used to run To form the "was doing" imperfect, take the infinitive ending in ഉക (uka), for