Hai Gaon was also a poet.
The language used by the Gaonim was at first Hebrew and Aramaic, and the latter remained the official speech of the Gaonate.

In course of time, Arabic replaced the Aramean dialect, and became the _lingua franca_ of the Jews.
The formal works of the Gaonim, with certain obvious exceptions, were not, however, the writings by which they left their mark on their age.
The most original and important of the Gaonic writings were their "Letters," or "Answers" (_Teshuboth_).

The Gaonim, as heads of the school in the Babylonian cities Sura and Pumbeditha, enjoyed far more than local authority.

The Jews of Persia were practically independent of external control.

Their official heads were the Exilarchs, who reigned over the Jews as viceroys of the caliphs.