Languages

While virtually all of the major languages which exist today are still present in The Space Game, a few languages are in heavy use throughout the solar system, or are noteworthy for other reasons:

English
English is the de facto official language of the solar system. It is the most widely spoken language on Earth, and is the language of commerce. Anyone employed by TLM will know English. The DnD equivalent would be the language "common."

Chinese
On Earth, there are about as many native Chinese speakers as native English speakers, though its use is less common in other places in the solar system. About half of players playing as the Earthling race will be able to speak Chinese.

Esperanto
Esperanto is a constructed language that is the official language of Novia. Novians speak only Esperanto, and intentionally do not learn any other languages. Some very high ranking individuals such as higher level managers or advanced scientist who are not from Novia may also know Esperanto.

Jovian Pidgin
Jovian Pidgin is a Pidgin language that is somewhat mutually intelligible with English. It is spoken by people who live around the satellites of Jupiter. Players who choose the Jovian race will be able to speak Jovian Pidgin. Players who choose the Worker class are also more likely to be able to speak Jovian Pidgin.

In addition to these, if your character is from a particular country on Earth, then it is reasonable to expect that they could speak the language of that country.