accuracy– Not making mistakes in a foreign language. A student who is obsessed about having every mistake corrected, usually Swiss, is called an accurist
advanced learner– a proficient user of a foreign language. One who can correct their teacher once or twice a term and still thinks it is clever to do so. A learner who could do so even more but has learnt that they are actually there to learn something and move up to the next level is defined as proficiency level.
affect– basically, emotional factors in the classroom, e.g. feelings towards L2, the teacher, native speakers etc. This noun is based on the first syllable, and correcting a teacher on this is a perfect example of producing negative affect with error correction.
affix– In a rare but not unique example of linguistic jargon being named after a childrens toy, affixes are named after the plastic model brand Airfix. This is due to sticking affixes onto the front of words (prefixes, mis- etc.) or end of words (suffixes, -ify etc.) being like a nerdy teenager sticks decals onto a badly painted model of a WWII Spitfire fighter plane.
agency– In linguistics, having agency means having control over your own language learning. How ironic then that agency is also the name for the companies that sell English courses in the UK etc. abroad by lying through their teeth about likely progress, extra charges, friendliness of host families etc. etc.
prefix and suffix– These affixes that go on the front (sub-, re- etc.) and back (-able, -ly etc.) of words are named after Asterix characters that always wandered into battle at the front of the phalanx not knowing how much trouble they were getting into (Prefix) or cowered at the back until Obelix found them (Suffix).
TBL– Task Based Learning- Although many of the details of this approach are still less clear than the (at least easy to understand) approach of PPP, the basic idea is to get students learning the vocab, grammar and functional language they need by basing the interactions and possibly the whole lesson and even syllabus on tasks (negotiating a menu, finding your way around the Hong Kong tube etc.) that students perform. As is clear from the random examples I gave, it is quite possible for such tasks to be nothing new and possibly totally unstimulating, and so it was to be in the first major TBL textbook series, Cutting Edge- which was pants. There are other theoretical and practical arguments against TBL, but the main point is that after 100s of books and research papers it has not changed the way English is taught in more than 1 percent of the classrooms of the world. More sensibly, recent textbooks seem to concentrate much more on what to teach rather than how to teach it.
TEFL– Teaching English as a Foreign Language. It was once quite ordinary to refer to the industry as TEFL and even say I am a TEFL teacher, but as the term has taken on a negative image of cowboy schools, underqualified teachers and all the other negative images people both inside and outside the industry might have. EFL teacher and the ELT industry are now much more generally used by people inside the industry, although of course the negative image rather than the word is the problem. I am therefore starting a campaign to reclaim the word TEFL, in the same way as the N word has become standard for rappers.
Complete list here.