Complex sentence: The only vowel that is regularly fronted before an/i/or/j/is short/a /: "gast"-- "gesti", "slahan"-- "slehis".
Split into simpler sentences: The only vowel that is regularly fronted before an/i/or/j/is short/a /. E.g. "gast"-- "gesti", "slahan"-- "slehis".