Earthian

Septimus Spink, sole survivor of the Earthian space ship...

An Earthian metallurgist could tell very easily that 'aluminum' was molybdenum...

Nowadays speakers on Twin Earth are well aware (thanks to chemistry) that their word 'water' does not refer to the Earthian stuff.

I inquired of one prominent Earthian: "What's of constructing ships and buildings...?"

I most likely will be the second Earthian to reach that planet. ...

According to Fodor's definition, it follows that 'water' in Twin Earthian means XYZ and not H2O.

I thought the females spoke Earthian to you. Improving their Earthian was why they asked for a couple.