T-V

Tandem Two people learn each other's languages by meeting regularly,

TEFL vs. TESL
Teach English as a Foreign Language vs. Teach English as a Second Language (see EFL vs. ESL)

TOEIC
Test of English for International Communication; a standardized exam that tests a person's ability to use English in business and everyday situations

TTT
Teacher Talking Time; the amount of time a teacher talks and the learner listens

Two way
bilingual environment in which L1 learners are taught L2 and vice versa at the same time

Virtual field trip
a collection of images, text and/or video from the World Wide Web that is gathered and packaged into a presentation on a certain topic