means The fleshy, muscular organ in the mouth used for tasting, swallowing, and forming speech — and, by extension, a language itself (your 'mother tongue').

from From Old English 'tunge,' tracing back to Proto-Germanic '*tungōn' (a cousin of German 'Zunge' and Dutch 'tong') and ultimately the Proto-Indo-European root '*dn̥ǵʰwéh₂s,' which also gave Latin 'lingua' and the English 'language.' The odd spelling — that silent '-gue' ending — is a later cosmetic flourish; earlier English happily wrote it 'tunge' or 'tonge.' From the start the word carried both meanings at once: the muscle in your mouth and the speech it produces, which is why a 'tongue' can mean a language across half the world's writing.