English Translation
Man, above all things, is a talking animal.
“Above all things” is often translated as 何よりもまず. But it’s a bad collocation in this sentence because 何よりもまず means “the first thing among others”. It can be even interpreted as “What human beings do first after being born is talking.” Babies cannot talk.
Also, 話す動物 sounds a bit unnatural.
My alternative translation is:
人はとりわけ、言葉を話す動物と言える。（ひとはとりわけ、ことばをはなすどうぶつといえる。）
何よりもまず is replaced with とりわけ, and 言葉を is followed by 話す動物. Ending with である is okay, but I personally prefer と言える (can be defined as), giving the entire context and tone.