lexicographer (n.)

• annotator
• cicerone
• commentator
• critic
• cryptanalyst
• cryptographer
• cryptologist
• decoder
• demonstrator
• dialectician
• dragoman
• editor
• etymologist
• exegete
• exponent
• expositor
• expounder
• glossarist
• go-between
• grammarian
• guide
• interpreter
• lexicologist
• linguist
• orthoepist
• paleographer
• philologist
• phonetician
• phonologist
• scholiast
• semanticist
• translator