what is it?
Gemination is the doubling of a word-final consonant that occurs in a small, fixed set of Turkish nouns borrowed from Arabic. When one of these nouns takes a suffix that begins with a vowel — such as a possessive or case ending — the final consonant is written and pronounced twice: hak becomes hakkım, his becomes hissi. Before a consonant-initial suffix, or when the word stands alone, the single consonant is kept. This behaviour is lexical: it must be learned word by word, and it does not apply to ordinary Turkish nouns.
when to use it
Vowel-initial suffix → double the consonant. Any suffix whose first letter is a vowel (possessives -ım/-im/-um/-üm, accusative -ı/-i/-u/-ü, dative -a/-e, etc.) triggers the doubling: hak + -ım → hakkım, hat + -ı → hattı.
Consonant-initial suffix → keep the single consonant. Suffixes that begin with a consonant (ablative -dan/-den/-tan/-ten, plural -lar/-ler, etc.) do not trigger doubling: his + -ten → histen, hak + -lar → haklar.
Bare form → single consonant. The dictionary (citation) form always shows the single consonant: hak, his, sır, hat.
Only for the affected lexical set. The words that geminate are a closed, Arabic-origin group: hak, his, sır, hat, hac, zıt, ret and a handful of others. Turkish dictionaries mark them with their geminated form, e.g. sır (-rrı), hat (-ttı). Regular nouns never double: at → atım, ev → evim.
formation
The rule is simple once you know which words are in the set. Before a vowel-initial suffix, write the final consonant twice, then add the suffix normally (including any vowel harmony). Before a consonant-initial suffix, attach the suffix to the bare stem as usual.
| stem | suffix | output form | meaning |
|---|---|---|---|
| hak | -ım (1sg poss.) | hakkım | my right |
| hak | -lar (plural) | haklar | rights |
| his | -i (3sg poss.) | hissi | his/her feeling |
| his | -ten (ablative) | histen | from the feeling |
| sır | -ımız (1pl poss.) | sırrımız | our secret |
| hat | -ı (accusative) | hattı | the line (acc.) |
| zıt | -ı (3sg poss.) | zıddı | its opposite |
Note that zıt → zıddı also shows consonant voicing (t → d) alongside the doubling. Both changes happen together before the vowel suffix.
examples in context
common pitfalls
Forgetting to double before a vowel suffix. Writing *hakım or *sırım is incorrect. The geminate is obligatory for these words: the correct forms are hakkım and sırrım.
Doubling before a consonant-initial suffix. The geminate only surfaces before a vowel. Before a consonant, the stem reverts to its single form. *hissten and *hakklar are wrong; the correct forms are histen and haklar.
Assuming the rule is predictable. Gemination is not a general phonological rule in Turkish — it is a lexical property of a small Arabic-origin set. Most nouns with a final consonant never double: at → atım (not *attım), ev → evim (not *evvim). Check the dictionary entry — words that geminate are marked with their doubled form.
Three sentences, graded here. Nothing is saved and no account is needed.
Bu iş senin ___, onu koruman lazım. (hak)
Fill in the blank with the correct form of the word in parentheses.