The word יִשְמָעֵאל is written with the tzeirei under the ayin and not under the aleph (like this: יִשְמָעאֵל). I think that the suffix אֵל refers to Hashem and therefore would have expected the tzirei to be under the aleph.
Is the positioning of the tzeirei intended to convey some message or is it just the result of some grammatical rule?