Ḫāʾ, Khāʾ, or Xe (خ, transliterated as ḫ (DIN-31635), ḵ (Hans Wehr), kh (ALA-LC) or ẖ (ISO 233)) is one of the six letters the Arabic alphabet added to the twenty-two inherited from the Phoenician alphabet (the others being ṯāʼ, ḏāl, ḍād, ẓāʼ, ġayn).
It is also one of the ten letters the Persian alphabet added from the twenty-two inherited from the Phoenician alphabet (the others being s̱e, ẕâl, zâd, ẓâ, ġayn, pe, che, že and gaf).
The pronunciation of خ is very similar to German, Irish, and Polish unpalatalised "ch", Russian х (Cyrillic Kha), Greek χ and Peninsular Spanish and Southern Cone "j".
The most common transliteration in English is "kh", e.g. Khartoum (الخرطوم al-Kharṭūm), Sheikh (شيخ), Kazakhstan (كازاخستان), Maha Sarakham (ماها ساراخام).
Ḫāʾ is written is several ways depending in its position in the word: ʾ b g d h w z ḥ ṭ y k l m n s ʿ p ṣ q r š t