Native U.S. speakers pick up the phonology of our language intuitively at a very early age. There are certainly kids who need speech teachers, but most do not. Nothing about phonology or speech production or the position of the tongue and palate is taught in school, and if it is spelled with a single letter "a" we just tend to think of it as "a vowel," in this case a "long" a. By the time we are learning to read, we are already quite well trained in the phonemes of English, and we just need to link up which letters stand for which phoneme. We need to know that the "a" in "lake" is a "long a," but we don't need to know what a "long a" is, or what we do with our mouths to produce it. I can't even remember how or why I learned the word "diphthong." It certainly wasn't in connection with English. I didn't really become conscious of the (obvious) fact that many of our "vowels" are diphthongs until I took singing lessons and had to think about the timing of "turning" the vowel. So many of us don't know that the "a" in "lake" is a diphthong because we've never been taught it and never needed to know.

it's definitely a diphthong. http://www.english-for-students.com/Diphthongs.html

Hi I'm a f/ high school english speaker but I'm pretty sure it is a diphthong b/c it makes a lay-ke sound. The emphasis on the a as an ay- makes me think it is, and I'm totally prepared to sound like a dummy, but take pleasure in the fact that most English speakers don't even know either.

Sounds like a diphthong to me..hm How else is the sound written if not /eɪ/, in you textbook? or whatever your read that from?

A diphthong is a sound formed by the combination of two vowels in a single syllable, in which the sound begins as one vowel and moves toward another (as in coin, loud, and side ). As for the word "lake" you can clearly hear only the sound one vowel "a" not the "e".