อ‍ย

Letter

 * 1) A conceptual letter for the sound resulting from the Southwest Tai cluster /ʔj/ and written อย in early Siamese inscriptions.  It is used as the corresponding letter to the Tai Tham letter  in works such as References 1 and 2 below.

Usage notes
Note that in Unicode, the presence of the zero width joiner in the spelling is essential. A specialised font is required to display it properly.