It seems that a standard has arisen for giving the digits of larger bases (up to hexadecimal) names in English. (Letters don't cut it, for purposes of pronunciation.) I only heard of it recently, when someone started using it while saying some hexadecimal numbers.

Decimal  Hex Doz  Digit name
-------  --- ---  ----------
     10   A   *   dek 
     11   B   #   el
     12   C       zen
     13   D       tris
     14   E       cat
     15   F       kink

These names come from various languages' names for the numbers - I surmise from Greek "deka", English "eleven", English "dozen", Greek "triskadeka", Spanish "catorce", and Spanish "quince".

A slight variation is used in dozenal, where 10 (12 in decimal) is called "do" (even though it's not a single digit) so that it will not be confused with the decimal "ten".