# -tu
## Afar
### Pronunciation

* IPA: /-tu/ [-tʊ]

### Suffix

-tu
* Form of -ytu used after nouns ending in consonants.

#### Declension
### References

* E. M. Parker, R. J. Hayward (1985) An Afar-English-French dictionary (with Grammatical Notes in English), University of London, →ISBN, page 228
* Mohamed Hassan Kamil (2015) L’afar: description grammaticale d’une langue couchitique (Djibouti, Erythrée et Ethiopie)‎, Paris: Université Sorbonne Paris Cité (doctoral thesis)

## Basque
### Alternative forms

* -du (see usage notes)

### Etymology

From Latin -tum, a past participle forming suffix. Basque borrowed Latin verbs in their participle form (for example, aditu (“to hear”) from audītum, neuter perfect passive participle of audiō (“I hear”)), with the ending being reinterpreted as a new verb forming suffix. Compare English -ate (verb-forming suffix).

### Suffix

-tu
* A verb-forming suffix.
    ‎euskara (“Basque”) + ‎-tu → ‎euskaratu (“to translate into Basque”)
    ‎ohera (“to, towards bed”) + ‎-tu → ‎oheratu (“to go to bed”)
    ‎gehi (“plus”) + ‎-tu → ‎gehitu (“to add”)
* Used to form adjectives, roughly corresponding to the English past participle forming suffix -ed.
    ‎gehi (“plus”) + ‎-tu → ‎gehitu (“augmented”)

#### Usage notes

* Takes the form -du after words ending in /l/ or /n/:
    ‎lagun (“friend”) + ‎-tu → ‎lagundu (“to help”)
* This is the only productive verb-forming suffix in modern Basque, having displaced the native suffix -i.
* Verbs taking this suffix have no synthetic forms (with the exception of ezagutu (“to know”)).

#### Derived terms
### References

* ↑ “-tu” in Etymological Dictionary of Basque by R. L. Trask, sussex.ac.uk

## Estonian
### Etymology

From Proto-Finnic *-t'oin. Cognate with Finnish -ton/-tön.

### Suffix

-tu (genitive -tu, partitive -tut, comparative -tum, superlative kõige -tum)
* -less

#### Derived terms
## Finnish
### Pronunciation

* IPA: /-tu(ˣ)/, [-t̪u(ʔ)]

### Suffix

-tu (front vowel harmony variant -ty, linguistic notation -tU)
* Alternative form of -ttu

### Anagrams

* -ut

## Franco-Provençal
### Pronoun

-tu
* postpositive form of te

## Garifuna
### Suffix

-tu
* nominalizing suffix deriving agent nouns of feminine gender (see -ti for masculine).
    Abuwagu ― to cook
    Abuwagutu ― chef (female)

## Latin
### Suffix

-tū
* ablative singular of -tus

## Old Irish
### Alternative forms

* -atu, -etu, -thu, -tiu

### Etymology

From Proto-Celtic *-tūts (stem *-tūt-; compare Welsh -tid), from Proto-Indo-European *-tuHts (whence Latin -tūs and Gothic -𐌳𐌿𐌸𐍃 (-dūþs)).

### Suffix

-tu m
* -ness, -ity

#### Inflection

Masculine t-stem :
| | Singular | Dual | Plural |
| Nominative | -tu | — | — |
| Vocative | -tu | — | — |
| Accusative | -taid$^N$ | — | — |
| Genitive | -tad | — | — |
| Dative | -taid$^L$ | — | — |
| Initial mutations of a following adjective: $^H$ = triggers aspiration $^L$ = triggers lenition $^N$ = triggers nasalization ||||

#### Derived terms
### Further reading

* Thurneysen, Rudolf (1940) D. A. Binchy and Osborn Bergin, transl., A Grammar of Old Irish, Dublin Institute for Advanced Studies, →ISBN, § 258, pages 165–66; reprinted 2017

## Old Norse
### Alternative forms

* þú
* -du, -ðu

### Pronoun

-tu (enclitic)
* enclitic form of þú
** Haralds saga hins hárfagra 41.
    Nú tóktu svá við sem várr konungr vildi.
** Lokasenna 24.
    En þik síða kóðu / Samseyju í / ok draptu á vétt sem vǫlur / vitka líki / fórtu verþjóð yfir / ok hugða ek þat args aðal
    ‎skalt (“shalt”) + ‎þú → ‎skaltu (“shalt thou”)
    ‎lát (“let (impr.)”) + ‎þú → ‎láttu (“let (impr.)”)

#### Usage notes

For reasons related to syntax, as well as Old Norse often explicitly stating the subject of verbs in the imperative, the verb is often followed by the subject pronoun. For þú, this is when it may take on an enclitic form. This is not to say, however, that whenever þú comes after a verb, it will always take an enclitic form. It could well stay separate for the sake of emphasis.
Which one of the variants -du, -ðu and -tu to use, is decided by the same rules that decide which dental suffix to take in the type 1 weak verbs. This form is used after hard consonants.

#### Descendants

This feature is also present in modern Icelandic verb conjugation, with its imperative forms with appended personal pronouns (though only in the second person).

#### See also

* -k

## Turkish
### Pronunciation

* IPA: /tu/

### Suffix

-tu
* Form of -tı after the vowels O / U.
    ‎al- (“to take”) + ‎-ın (“to take offense”) + ‎-tı → ‎alıntı (“quotation, citation”)
    ‎ak- (“to flow”) + ‎-ın + ‎-tı → ‎akıntı (“flow, current, stream”)
    ‎çıt (“click or crack sound”) + ‎-ır + ‎-tı → ‎çıtırtı (“clicking, cracking”)
    ‎mor (“purple”) + ‎-ar (“to turn purple”) + ‎-tı → ‎morartı (“bruise, a purplish spot”)