Comparison between European languages - Diphthong

Comparison between European languages - Diphthong

 

When two vowels meet adjacent to each other, they may form a diphthong. But how can we discern whether they are diphthong or not. From the analysis on Greek, I have found that:

When the last vowel is u or i, then it will mostly likely form a diphthong.

        (ai, ei, oi, au, eu, ēu, ou, ui - ai, ei, oi, au, ou, eu, hu, ui)

 

But does it holds for other European languages?

 

The picture becomes quite complex but interesting:[1]

1.          The rule seems to hold with some exceptions.

2.          Some languages added the semi-vowels to form diphthongs. E.g. English uses Ə, while Spanish uses j and w to form diphthongs (ja, je, jo, ju and wa, we, wi, wo.) Besides, Spanish has less diphthong in contrast to Greek, it has only ai, au, ei, eu, and oi. Thus, English and Spanish are mostly likely to form triphthongs too.

3.          Some languages, like Swedish and Danish, have no diphthongs, or at least very few (source: http://www.genealogi.se/sprakeng.htm).

4.          If we want to extend the rule to wider use, then I can re-model the rule as the last vowels will likely to be the vowel with upper tongue positions. The diphthongs used in British English shows the positions. ʊ and i (new symbol for IPA is I)

5.          When we expand our search for diphthongs, we can find that the upper "corridor" [2]is used more as the last vowels of a pair of diphthong. E.g. u, ʊ on the upper right, and on the upper left [I, Y] and [i, y](on the left-most corner) are widely used. With the addition of some semi-vowels [Ə] or approximants [w, j, ɥ], then we will have most of the other diphthongs.

6.          Since using approximants as the first vowels, then it is possible to use more vowels, rather than that in the upper corridor, to form vowels. If we don't count them, then we can limit our search.

7.          But some languages, use the left side of the vowel table, e.g. [e,ø], [e, œ[3]] æ, [a] in the last vowels. These usages are not prominent and usually used sparsely in some languages only.

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[1] Diphthongs used in many languages can be seen in http://en.wikipedia.org/wiki/Diphthong.

[2] Though ʉ can be taken as a member of this corridor, but it is used only in Norwegian ( /æʉ/ as in sau, "sheep"), so I don't list it here. Other five diphthongs in Norwegian use I and Y as the last vowels.

[3] This one used in Icelandic /jœ/ as in jötunn, "giant".