Maser voice-streams, also known as the Oswaft language, were the communications medium and weapons of the Oswaft species.
Their language was complex and highly sophisticated, with communication being performed by modulating radio-frequency waves with their brains. The vacuum-breathers were also able to "speak" a picture-message intended to convey visual reality rather than pure ideas.
Oswaft were able to employ this type of communication in the form of maser bolt. They referred to this as "shouting" at their opponent. The Oswaft were capable of destroying Imperial fighters in a single "shout", and could also destroy unshielded starships. However, maser voice-streams were generally ineffective against capital ship shielding.