[7] For example, in the sentence conquistar-se-á ("it will be conquered"), the reflexive pronoun "se" appears between the stem conquistar and the future tense affix á.
[9] Colloquial Turkish exhibits an instance of a mesoclitic where the conjunction enclitic de ("also, as well") is inserted after the gerundive suffix -e connecting the verb stem to the potential suffix -(e)bilmek,[10] effectively rendering it in its original auxiliary verb form bilmek (to know).
Both variants carry similar meaning and phonological makeup, but the special clitic is bound to a host word and is unaccented.
[11] Some clitics can be understood as elements undergoing a historical process of grammaticalization:[13] lexical item → clitic → affix[14] According to this model from Judith Klavans, an autonomous lexical item in a particular context loses the properties of a fully independent word over time and acquires the properties of a morphological affix (prefix, suffix, infix, etc.).
As a result, this term ends up being applied to a highly heterogeneous class of elements, presenting different combinations of word-like and affix-like properties.
There is no natural, clear-cut boundary between the two categories (since from a diachronic point of view, a given form can move gradually from one to the other by morphologization).
An affix syntactically and phonologically attaches to a base morpheme of a limited part of speech, such as a verb, to form a new word.
Many Indo-European languages, for example, obey Wackernagel's law (named after Jacob Wackernagel), which requires sentential clitics to appear in "second position", after the first syntactic phrase or the first stressed word in a clause:[14][20] English enclitics include the contracted versions of auxiliary verbs, as in I'm and we've.
Linguists Arnold Zwicky and Geoffrey Pullum argue, however, that the form has the properties of an affix rather than a syntactically independent clitic.
[26] For the Spanish object pronouns, for example: Portuguese allows object suffixes before the conditional and future suffixes of the verbs:[27] Colloquial Portuguese allows ser to be conjugated as a verbal clitic adverbial adjunct to emphasize the importance of the phrase compared to its context, or with the meaning of "really" or "in truth":[28] Note that this clitic form is only for the verb ser and is restricted to only third-person singular conjugations.
It does not need to concord with the tense of the main verb, as in the second example, and can be usually removed from the sentence without affecting the simple meaning.
In the Indo-European languages, some clitics can be traced back to Proto-Indo-European: for example, *-kʷe is the original form of Sanskrit च (-ca), Greek τε (-te), and Latin -que.
Serbo-Croatian: the reflexive pronoun forms si and se, li (yes–no question), unstressed present and aorist tense forms of biti ("to be"; sam, si, je, smo, ste, su; and bih, bi, bi, bismo, biste, bi, for the respective tense), unstressed personal pronouns in genitive (me, te, ga, je, nas, vas, ih), dative (mi, ti, mu, joj, nam, vam, im) and accusative (me, te, ga (nj), je (ju), nas, vas, ih), and unstressed present tense of htjeti ("want/will"; ću, ćeš, će, ćemo, ćete, će) These clitics follow the first stressed word in the sentence or clause in most cases, which may have been inherited from Proto-Indo-European (see Wackernagel's Law), even though many of the modern clitics became cliticised much more recently in the language (e.g. auxiliary verbs or the accusative forms of pronouns).
These include phrases containing conjunctions (e. g. Ivan i Ana "Ivan and Ana"), nouns with a genitival attribute (e. g. vrh brda "the top of the hill"), proper names and titles and the like (e. g. (gospođa) Ivana Marić "(Mrs) Ivana Marić", grad Zagreb "the city (of) Zagreb"), and in many local varieties clitics are hardly ever inserted into any phrases (e. g. moj najbolji prijatelj "my best friend", sutra ujutro "tomorrow morning").
In cases like these, clitics normally follow the initial phrase, although some Standard grammar handbooks recommend that they should be placed immediately after the verb (many native speakers find this unnatural).
Colloquial interrogative particles such as da li, dal, jel appear in sentence-initial position and are followed by clitics (if there are any).