English Hyphenation file looks something like this...
LEFTHYPHENMIN 2
RIGHTHYPHENMIN 3
COMPOUNDLEFTHYPHENMIN 2
COMPOUNDRIGHTHYPHENMIN 3
.a2ch4
.ad1d4
.am5at
1, 2, 4 and 5 numbers are added next to characters. Does it mean it is OK to hyphenate next to "a" but not OK to hyphenate next to "ad"?