"He teaches us the words."
No, the conjugation of "apprendre" needs to match that of the subject (il in this sentence).
J'apprends, Tu apprends, Il/Elle apprend,
nous apprenons, vous apprenez ils/elles apprennent
The "s" that you see at the ends of verbs doesn't have much to do with how plural a word is, it is just the conjugation (adjectives are a different story).