When starting to learn German from the EUP book "Teach yourself German" many years ago, I gathered that German long e was pronounced similarly to the French é. Thus, for example, sehen, to see, would be pronounced, very approximately, as English ZAY-in, IPA /ze:n/. However, on beginning the on-line Duolingo German course recently, I notice that the speaker pronounces the word more like ZEE-in, IPA /zi:n/. Is this a question of local accent, perhaps, or have I been mistaken all these years?
You are almost right in the pronunciation that you expect. However, the vowel of the second syllable does not completely disappear, Wiktionary gives the pronunciation as [ˈzeːən]. That may have confused you, given that the difference between a long e and a long i is often difficult for English speakers to hear as previous questions show.
We don't have an audio sample, so this is only speculation:
The standard pronunciation of 'sehen' is transcribed as [ˈzeːən], while [ˈzeːn] is known as an often occurring version. (Duden Aussprachewörterbuch)
Speakers often don't articulate the schwa sound [ə] clearly when a word ends with an -en, and then it may sound a bit like [ˈzeːɪn].
If, however, someone clearly pronounces sehen as [ˈziːn], that would be wrong in terms of standard German pronunciation.
Here is the »Österreichische Aussprachedatenbank Adaba« (Austrian pronunciation database) where you can listen to the correct pronunciation of thousands of words:
It contains thousands of audiofiles of standard pronunciation of German word for the three standard variations of German (Austrian German, German German and Swiss German), each spoken by a female and a male speaker (red triangle = female speaker, blue = male).
I can identify the both Austrian speakers by their voices, they have been news speakers in TV some years ago, so they are professional speakers. I don't know who the other speakers are, but I guess, they are professional speakers as well. So the audio files really let you hear what standard is.
How to use it:
Enter (part of) a word in the second area titled »Suche« (search). You can search orthographic and even phonetic (if you're not sure about the correct spelling).
When you click on the magnifying glass, you get a list of hits in the first area titles »Ergebnis« (result). If you click an item of the list, the IPA-phonetics will be shown for the standard pronunciation of this word for each of the three standard variations. If there are more than one "official" pronunciations for a word, then all of them will be displayed.
Type »sehen« into the field in the Suche-window and click the glass. You get a list of about 20 words containing »sehen« in the Ergebnis-window, among them »sehen« itself. Click it!
The pronuciations are:
- In Austrian Standard German: [ˈseː.ɘn] and [ˈseːn]
There almost never is a voiced alveolar fricative [z] in Austrian German, so »sehen« starts with a voiceless alveolar fricative [s] in Austrian German.
One possibility is to speak two vowels, which gives two syllables. The first is a long close-mid front unrounded vowel [eː] followed by a syllable boundary ([.]) which you can hear as a very short break and then a short close-mid central unrounded vowel [ɘ].
The other posibility is to speak it as one syllable with just one vowel. (This is not allowed in German Standard German or Swiss Standard German, only in Austrian Standard German)
- In German Standard German: [ˈzeː.ən]
Starts with [z], has two syllables, and the vowel of the last syllable is a mid central vowel [ə]
- In Swiss Standard German: [ˈzeː.ɘn] or [ˈzeː.ən]
One version is the same as the German version, the other just uses an other vowel in the second syllable.
Note, that this database only contains the standard pronunciations. You will not find dialect pronunciations there or pronunciations of colloquial speech. Those pronunciations can differ very much from the standard, so you sometimes might not understand dialect pronunciation. (This can be hard for German native speakers too.) But everybody who speaks German will understand you if you use any of the standard pronunciations.