How do they know there was a great vowel shift in english before the invention of tape recorders?

Question

No one can hear how people pronounced words back then, so what method(s) do linguists use to determine that there was a vowel shift in English between 1200 and 1600 (or whenever it was)?

Answer 1

Spelling of Modern and Middle English is a big part of the evidence (along with modern pronunciation).

But notice some of the specific TYPES of evicence involved:

a) for Modern English, the spelling & pronounciation of clearly related words:
e.g., the vowels of "please" and "pleasant"

b) for MIDDLE English, the spelling of
--- RHYME words
-- doubled vowels indicating vowel "length"
---comparison with French and Latin spellings

This is laid out in more detail and with example in the following page:
http://asstudents.unco.edu/faculty/tbredehoft/UNCclasses/ENG419/GVS.html

But a note or two may help -

If you've studied other European languages, esp. the Romance languages, you will know that the pronunciations of several of their "long vowels" is quite different from that of many Modern English words, while that for the "short vowels" may be quite close".

You may ALSO have seen that in these languages the "short" and "long" versions of the same vowel are more clearly and consistently related than they are in English. This of itself suggests that at some point in the history of English these long vowels shifted. The questions are basically how (much debated!) and when (= from Middle to Modern English as the evidence being mentioned here makes clear).

More specifically, note the names we use for the following notes in the scale. These syllables, borrowed from Latin, retain the Latin pronunciation of the long vowels:
* "re" -- the original long e - sounds = more like our word "ray", and what WE call "long a" (as in "gate")
* "mi" -- long i - sounds more like "me" in English, that is, what we call "long e"

Comparing the long & short versions of vowels:
* the longe e of "re" is related to the our short e (/eh/ as in "get")
* long i of "mi" is related to our short i (compare "mit")

Answer 2

It could be that the spelling system merely changed although it's true that dictionaries do tend to make spelling more conservative, kinda freezing it in time. Before dictionaries, or spelling standards, people tended to write phonetically (or as best they could with the Latin alphabet). However, there have actually been 'shifts' SINCE recording methods have been invented. For example, in the Edwardian era, 'lord' was heard being pronounced 'lard', 'father' as 'fayther' and so on but still spelled the same...

Answer 3

Spelling. Dictionaries are a new invention too. People generally spelled words many different ways as the sounds change.