Yes/No questions in Turkish are typically formed using the question particle mi / mı / mu / mü, which follows I-Type vowel harmony based on the preceding vowel.

Formation:

The question particle is written as a separate word and comes after the verb (or the word being questioned). Personal suffixes are attached to the question particle, not the verb itself.

Verb (conjugated for tense/mood, but usually without personal suffix) + mi/mı/mu/mü + Personal Suffix (if applicable)

Examples:

• Present Continuous:
  Geliyor musun? (Are you coming?)
  (geliyor + mu + sun)
• Present Simple/Aorist:
  Okur musun? (Do you read? / Would you read?)
  (okur + mu + sun)
• Past Simple (-di):
  Yaptı mı? (Did he/she do it?)
  (yaptı + mı - no personal suffix for 3rd person singular)
  Yaptınız mı? (Did you (pl./formal) do it?)
  (yaptı + nız + mı - Note: Suffixes can sometimes attach to verb, then particle: Yaptınız mı? or Yaptı mıydınız? - latter is more complex) Simpler: Siz yaptınız mı? (You did do it?)
• Future Tense:
  Gelecek misin? (Will you come?)
  (gelecek + mi + sin)
• With "to be" (using değil for negative):
  Bu kitap mı? (Is this a book?)
  Hasta mısın? (Are you sick?)
  Öğretmen değil mi? (Isn't he/she a teacher?)

The question particle mi takes the full stress of the sentence.