The Organians, introduced in The Original Series, make their first canonical appearance as non-corporeal aliens. At the end, they discuss that they should prepare for a first contact with humans, which happened in Errand of Mercy.
When Hoshi is struggling with the alien's language, suggesting it is more reminiscent of a mathematical equation, T'Pol states that mathematics is sometimes considered a form of language. In 'Observer Effect' (#4.11), Hoshi would later use the same argument when trying to break the lock-out code of the decon chamber. The fact that she succeeds on that occasion proves that she has mastered that "language" in the meantime.