Turkish, similarly to other Turkic languages, is a highly agglutinative language, in that much of the grammar is expressed by means of suffixes added to nouns and verbs. It is also very regular, comprising few (and usually predictable) exceptions. For example, evlerden "from the houses" can be analysed as ev "house", -ler (plural suffix), -den (ablative case, meaning "from"); gidiyorum "I am going" as git "go", -iyor (present continuous tense), -um (1st person singular = "I").
It is also a very strongly left-branching language : modifiers always come before what they modify, exclusive use of postpositions, finite verbs always being at the end of a clause. There are two main classes of inflectable words, nouns and verbs, a given root being generally either verbal or nominal but not both.
Another characteristic of Turkish is vowel harmony. Most suffixes have two (front/back distinction) or four (front/back + rounded/unrounded distinction) different forms, the choice between which depends on the vowel of the word's root or the preceding suffix: for example, the ablative case of evler is evlerden "from the houses" but, the ablative case of başlar "heads" is başlardan "from the heads".
Verbs have six grammatical persons (three singular and three plural), various voices (active and passive, reflexive, reciprocal, and causative), and a large number of grammatical tenses. Meanings such as "not", "be able", "should" and "if", which are expressed as separate words in most European languages, are usually expressed with verbal suffixes in Turkish. A characteristic of Turkish which is shared by neighboring languages such as Bulgarian and Persian is that the perfect tense suffix (in Turkish -miş-, -müş-, -mış-, or -muş-) often has an inferential meaning, e.g. geliyormuşum "it would seem (they say) that I am coming".
Verbs also have a number of participial forms, which Turkish makes much use of. Clauses which begin with "who" or "because" in English are generally translated by means of participial phrases in Turkish. These forms are often nominal forms derived from the verb. For example, olmadığında "when (s)he is not here, when there's no(t)", decomposes as ol- "be, become", -ma "negative", -dık (dığ before a vowel) "realis nominal suffix", -ı(n) "3rd person possessive suffix" and finally -da "locative/stative suffix", "in, at". This form could also be translated as a nominal phrase, "in his/her/its absence". Such nominals also work as head-modifiers. Example: Küçük kedi, dün getirdiğim sütü içti. "The little cat drank the milk I brought yesterday.", where getirdiğim "(that) I brought" analyzes as getir- "bring", -dik same suffix as in olmadığında and -im "1st person sg possessive suffix". This is also a nominal derived from a verb, yet it determines sütü "the milk", definite accusative form of süt. Morphology
Turkish words are routinely formed through the attachment to a stem (gövde) of one or more suffixes (ekler). A stem may be a root (kök) or further analyzable into parts. Turkish suffixes fall roughly into two classes: constructive suffixes (yapım ekleri) and inflectional suffixes (çekim ekleri). A constructive suffix makes a new word from an old one, that is, it is a derivational suffix. An inflectional suffix indicates how a word is used in a sentence.
The vowels of suffixes undergo vowel harmony. When a suffix is attached to a stem, the vowel in the suffix generally agrees in frontness or backness and in roundedness with the last vowel in the stem or of the preceding suffix.
Some suffixes show two-way vowel harmony between e and a, for example the plural suffix -ler/-lar. The e form is found after a syllable with i, e, ö or ü (e.g. evler "houses", günler "days"), and also after certain Arabic or French borrowings such as saatler "hours, clocks", kalpler "hearts". Other suffixes show four-way vowel harmony between i, ı, u, ü, for example the possessive ending -im/-ım/-um/-üm "my". These endings are found after syllables containing their own vowels or after e, a, o, ö respectively (e.g. evim "my house", gözüm "my eye", etc.)
No vowel harmony involves o and ö. Vowel harmony only affects two consecutive vowels: the very common continuous verbal suffix -iyor has only its first vowel changing: -iyor, -üyor, -ıyor, -uyor, the vowels following being always back (rounded) vowels, -iyor-um, -iyor-lar, never *-iyör-üm, -iyör-ler.
A Turkish suffix can be called enclitic if its vowel undergoes vowel harmony, agreeing with the last vowel of the stem the suffix is attached to.
Gender Turkish lacks grammatical gender. The English third-person singular pronouns she, he, and it all correspond to a single Turkish pronoun, o. Many given names in Turkish are unisex, so it is entirely possible to describe someone in the Turkish language without their gender being discernible from grammatical context.
Person Turkish has a strong T–V distinction, using the second-person plural as the formal form, as in French and many other languages.
Turkish also uses various honorifics.
T–V distinction Family members and friends speak to one another using the second singular person sen, and adults use sen to address minors. In formal situations (meeting people for the first time, business, customer-clerk, colleagues) plural second-person siz is used almost exclusively. In very formal situations, double plural second-person sizler may refer to a much-respected person. Rarely, third-person plural conjugation of the verb (but not the pronoun) may be used to emphasize utmost respect. In the imperative, there are three forms: second person singular for informal, second person plural for formal, and double plural second person for very formal situations. Thus, the imperative forms of the verb gelmek, "to come", are gel (second person singular, informal), gelin (second person plural, formal), and geliniz (double second-person plural, very formal). The very formal forms are not frequently used.
Honorifics Turkish honorifics generally follow the first name, especially if they refer to gender or particular social statuses (e.g. <name> Bey (Mr.), <name> Hanım (Ms.), <name> Öğretmen (teacher)). Such honorifics are used both in formal and informal situations. A newer honorific is Sayın, which precedes the surname or full name, and is not gender-specific. (e.g. Sayın Name Surname, or Sayın Surname, or Sayın Name Bey/Hanım). They are generally used in very formal situations. While these honorifics are normally used in pre-position to Turkish first names, for foreigners, names are preceded by Bay (Mr.) or Bayan (Ms.): Bay [Fox] Mulder, Bayan [Dana] Scully (cf. Fox [Mulder] Bey, Dana [Scully] Hanım, if these names were Turkish).
Turkish terminology In the Turkish terms for the constructive and inflectional endings, three roots are involved: ek "supplement, affix" (notably Turkish has no prefixes) yap- "make" çek- "pull, draw" For the last two verbal roots, the constructive suffix -im can be added to form nouns for instances of the actions denoted by the roots: yapım "construction"; "derivation". çekim "[a] pull or draw" (or a "take" in cinema). Either of these nouns can be compounded with the noun ek, resulting in an indefinite compound (belirtisiz tamlama), the sign of which is the inflectional suffix -i attached to ek: yapım eki "structure-suffix"; "derivational suffix". çekim eki "inflection-suffix". The inflectional suffix -ler comes before the -i to form the plural, so yapım ekleri, çekim ekleri.
Many words in Turkish— particularly many grammatical terms— are neologisms invented to replace earlier words borrowed from Arabic or Persian, which have largely been successful at permanently superseding the previously used foreign terms. (See the main article on Turkish language.) In some cases, the foreign term continues to be in use alongside the neologism.
Parts of speech There are nine parts of speech (söz türleri "word-kinds") in Turkish. noun (isim or ad "name"); pronoun (zamir "inner being", or adıl from ad); adjective (sıfat "role, quality", or önad "front-noun"); verb (fiil "act, deed", or eylem "action" from eyle- "make, do"); adverb (zarf "envelope", or belirteç from belir- "determine"); postposition (ilgeç from ilgi "interest, relation"); conjunction (bağlaç from bağ "bond"); particle (edat, or ilgeç); interjection (nidâ [dated], or ünlem from ün "fame, repute, sound"). Postpositions are analogous to prepositions in English, the main difference being that they follow their objects. Postpositions can be considered particles, but there are particles in Turkish that are not postpositions.
Only nouns, pronouns and verbs are inflected in Turkish. An adjective can usually be treated as a noun or pronoun, in which case it can also be inflected. Inflection can give a noun features of a verb such as person and tense. With inflection, a verb can become one of the following: verbal noun (isim-fiil); verbal adjective (sıfat-fiil) or participle (ortaç); verbal adverb (zarf-fiil) or gerund. These have peculiarities not shared with other nouns, adjectives or adverbs. For example, some participles take a person the way verbs do. Also, a verbal noun or adverb can take a direct object. Some verbal nouns are not inflected forms in Turkish but are borrowed from Arabic or other languages.
In Turkish, an ascriptive clause can be composed of a common noun standing alone as the Predicative, both the Subject and the Predicator being implicit and assumed from the situation. Example: köpek – "dog" Köpek. – "It is a dog." This means that both a noun and a verb can alone constitute an affirmative clause in Turkish, which is not the case in English.
There are two standards for listing verbs in dictionaries. Most dictionaries follow the tradition of spelling out the infinitive form of the verb as the headword of the entry, but others such as the Redhouse Turkish-English Dictionary are more technical and spell out the stem of the verb instead, that is, they spell out a string of letters that is useful for producing all other verb forms through morphological rules. Similar to the latter, this article follows the stem-as-citeword standard. Infinitive: koşmak ("to run") Stem: koş- ("run")
In Turkish, the verbal stem is also the second-person singular imperative form. Example: koş- (stem meaning "run") Koş! ("Run!")
Many verbs are formed from nouns by addition of -le. For example: köpek – "dog" köpekle – "dog paddle" (in any of several ways)
The aorist tense of a verb is formed by adding -(i/e)r. The plural of a noun is formed by suffixing -ler. Hence, the suffix -ler can indicate either a plural noun or a finite verb: Köpek + ler – "(They are) dogs." Köpekle + r – "S/he dog paddles."
Most adjectives can be treated as nouns or pronouns. For example, genç can mean "young", "young person", or "the young person being referred to".
An adjective or noun can stand, as a modifier, before a noun. If the modifier is a noun (but not a noun of material), then the second noun word takes the inflectional suffix -i: ak diş – "white tooth" altın diş – "gold tooth" köpek dişi – "canine tooth"
Comparison of adjectives is not done by inflecting adjectives or adverbs, but by other means (described below).
Adjectives can serve as adverbs, sometimes by means of repetition: yavaş – "slow" yavaş yavaş – "slowly"
Word order A general rule of Turkish word order is that the modifier precedes the modified: adjective (used attributively) precedes noun; adverb precedes verb; object of postposition precedes postposition.