Bulunma hâli — the locative case
Where English has separate prepositions 'in', 'on', and 'at', Turkish bundles all of them into a single suffix glued onto the noun. ev (house) → evde (at home, in the house, on the house — context decides). The suffix has FOUR forms because of vowel harmony AND a consonant-driven softening rule. Front vowel → -de. Back vowel → -da. After certain hard consonants (ç, f, h, k, p, s, ş, t), the d turns into a t: → -te / -ta. So: evde (at home), okulda (at school), ofiste (at the office), kitapta (in the book).
Front vs back: -de or -da
First check the last vowel. Front vowel (e, i, ö, ü) → -de. Back vowel (a, ı, o, u) → -da. ev → evde (front e). şehir → şehirde (front i). göz → gözde (front ö). okul → okulda (back u). araba → arabada (back a). kız → kızda (back ı).
The 'fıstıkçı şahap' consonants
After the eight unvoiced consonants — ç, f, h, k, p, s, ş, t — the suffix's d changes to t. Turkish students memorize them with the mnemonic phrase 'fıstıkçı şahap' (peanut-vendor Şahap), which contains them all. kitap → kitapta (in the book — p triggers t). ofis → ofiste (at the office — s triggers t). uçak → uçakta (on the plane — k triggers t). Fransa ends in a (a vowel, not a consonant) so → Fransa'da (in France).
Putting it with var/yok
Combine the locative with what you learned in lesson 5. Çantada kitap var = 'There is a book in the bag' (literally 'in-bag book exists'). Masada çay yok = 'There's no tea on the table'. Evde kedim var = 'I have a cat at home' (literally 'at-home my-cat exists'). The locative usually comes BEFORE the existing/possessed thing — Turkish prefers location → object → var/yok.
With the 'to be' endings
Add personal endings to a locative noun and you get 'I am at X', etc. Evdeyim = 'I am at home' (ev + de + y + im, with the buffer y because -de ends in a vowel). Okuldasın = 'You are at school'. İstanbul'dayız = 'We are in Istanbul'. (Proper nouns get an apostrophe before the case ending — purely a spelling convention to keep the name visible.)
Common locations
evde (at home), okulda (at school), işte (at work), ofiste (at the office), kahvede (at the café), otelde (at the hotel), mağazada (in the store), parkta (in the park), arabada (in the car), otobüste (on the bus). Note işte uses the -te form because iş ends in ş (a fıstıkçı şahap consonant).
