Virtually every language that uses the Latin alphabet follows some version of this plan for spelling vowels, not just Germanic ones. There is a reason the International Phonetic Alphabet uses the 5 basic vowel symbols /a/, /e/, /i/, /o/, /u/ this way.

As a native English speaker, this is also helpful with learning Vietnamese, which also uses the Latin alphabet.

Another thing an English speaker needs to learn about Germanic vowel is that they're all monophthongs.

In English, most vowel letters end up being diphthongs, and speakers have trouble pronouncing vowels without putting a diphthong-like "curve" to the end of the vowel. For example, German "so" or Scandinavian "så" have a single vowel, whereas English "so" has a diphthong that makes it rhyme with "sew" /soʊ/.

Some of the Germanic vowels are also quite different. "e" and "i" exist in English ("men", "bin", though English doesn't have the long versions, as in German "mehr"), but "u", "ü" and "y" don't.

"o" is interesting in that it only exist a silent mouth shape at the beginning of certain w- words such as "what" and "where" (/ʍ/). The English "o" used in words like "move" is different.

> In English, most vowel letters end up being diphthongs, and speakers have trouble pronouncing vowels without putting a diphthong-like "curve" to the end of the vowel.

This is overstated. I'll repeat that same sentence with diphthongs replaced by underscores:

In English, m_st v_wel letters end up being diphthongs, and speakers have trouble pron__ncing v_wels with__t putting a diphthong-l_ke "curve" to the end of the v_wel.

And "pronouncing" and "without" use digraphs for the diphthong. But even counting them, or double-counting them, or counting the "e" in like as also "being a diphthong", that doesn't look like "most vowel letters" to me.

The point wasn't to pedantically count diphthongs, it's the idea that English is biased towards them in a way that Germanic languages aren't, and which affects their pronouncation if left uncorrected. If it helps, replace "most" with "many".

This all depends on dialect, of course. Words like "ride" can occur both as diphthong (/ɹaɪd/) and monophthong (/ɹa:d/). Southern American dialects have things like vowel breaking that further puts a spin on vowels.

e sounds more like `eh` though (at least in latin-derived languages and japanese). Pronouncing it `ay` is generally seen as a strong english accent.

\e\ is a sound that is basically impossible to represent unambiguously to English speakers, without falling back to how it's used in words ('e' as in 'ten', for example).

`eh` and `ay` can both easily be read as a dipthong that would be represented as `ei` in any reasonably spelled language (like Finnish).

To keep things clear: the notation you'd typically want to use with IPA when taking about sounds (phones) is [e], as in this case, and use /e/ (with forward slashes) when taking about phonemes. Not to nitpick on you specifically, I see a lot of ad-hoc notations in these comments.

"ei" is more "ey" tho.

I think t-eh-n is pretty illustrative of why eh works better than "ay" either way - ay is much much closer to ey and so ei.

Depends on the language.

In some languages it's /ɛ/ (English "eh"), in others it's /e/ (Scottish English "ay"), and in yet others it's /e̞/ (halfway between the two). It's rarely /ɛɪ/ ("ay" in most dialects of English), though it appears in many other languages written as something other than "e".

Dutch is an interesting case: /ɛ/, /e/, and /ɛɪ/ are all different phonemes (short "e", long "e"/"ee", and "ei"/"ij" respectively).

Many only have one. Greek just has /ɛ/. Japanese just has /e̞/.

"Germanic" is a bit general, and pronounciations differ. The letter "u" is indeed "ooh" in German, but in Norwegian that sound is assigned to the letter "o", and the letter "u" (as in French) sounds like German "ü" (a sound that native English speakers are ridiculously bad at).

Also, Danish is just completely weird. I remember a Danish friend laughing at me once for pronouncing the Danish/Norwegian word "dag" (day) in Norwegian. There it's pronounced somewhat like the English "dug", but with a longer "ah" sound in the middle. In Danish it's pronounced like the English "day". WTF?

In short, there are no such general rules for "Germanic" languages, there are huge differences.

> pronouncing the Danish/Norwegian word "dag" (day) in Norwegian. ... In Danish it's pronounced like the English "day". WTF?

This is consistent with the pronunciation of "jeg" (=I, as in myself) in Norwegian, where the 'g' is a soft sound.

Spanish native speaker here, but I know a little of German.

In the books of "Dora the Explorer", usually the letter "i" in Spanish is replaced by the sound that makes "ee" instead of the sound of "e". So your first list should be

"ah, ay, ee, oh, ooh"

Downsides of trying to illustrate sounds with writing without using IPA (which I do not know enough of). I'm sure we are saying the same thing.

This has been quite a stumblingblock for the English persons I have been challenged to teach a bit of Scandinavian and/or German over the years. I remember one particularly challenging Cambridge graduate, otherwise sharp as a tack, who had enormous trouble with the the concept that vowels in general are not diphtongs, and that it doesn't really behove an Englishman to giggle over this quaint continental anomaly.

Fascinating; my son is just learning reading (English), and we start with those 'germanic' (i.e. short) vowel sounds as the default way of sounding, then try the longer sounds if it doesn't sound right (or has a modifier).