The addition of a letter or syllable to the beginning of a word. A kind
of metaplasm.
Examples
Addition of an initial letter: Adown we tumbled. To say "gnatus" for "natus"
Terence Addition of an initial syllable: By going to Achilles. That were to enlard his fat-already pride. —Shakespeare, Troilus and Cressida 2.3.194-195 To say "tetuli" instead of "tuli"