# Could you tell which pictures, which depict how the vowel chart is positioned inside our mouth, are accurate?

Ok, we all know that the vowel chart diagram is drawn like this

Ok, that is the model, but how the vowel chart is positioned inside our mouth or how the tongue in the reality is placed according to the diagram?

We got the X-rays of Daniel Jones of 4 extreme point [i, u, a, ɑ] as showed in the following diagram:

Wikipedia Ok, It seems that the X-rays of Daniel Jones could be drawn as the followings:

Now, here is quite confusing?

Some websites interpret how the vowel chart is positioned inside our mouth like the following (Interpretation 1):

Other websites interpret how the vowel chart is positioned inside our mouth like the following (Interpretation 2):

However, other websites interpret like this (Interpretation 3):

So, which Interpretation is accurate (Interpretation 1, 2 or 3)?

I think the Interpretation 1 is the most accurate because it is pretty close the X-rays of Daniel Jones. But I am not sure about that.

In the Interpretation 2, it seems that the author implies the position of the tongue of /i/ & /a/ is way too close to the front of the mouth. However, in the X-rays of Daniel Jones, the position of /i/ & /a/ is a bit retracted & is not too lose to the front of the mouth

Seem there is a lack of standard of how to depict how the vowel chart is positioned inside our mouth. That is causing a lot of confusing, right?

• What you must realize is that none of these set out to be inaccurate. Thus all of these are, to the best of their author's abilities, as accurate as they could make it. So if you think they are significantly different you must look at when the work was done, who did the work, and what qualifications they had. Then pick which one you think is best for you. I'm sure not everyone pronounces the same thing the same way either.
– Jim
Sep 15, 2015 at 3:10
• @ Jim, in the Interpretation 2, it seems that the author implies the position of the tongue of /i/ & /a/ is way too close to the front of the mouth. However, in the X-rays of Daniel Jones, the position of /i/ & /a/ is a bit retracted & is not too lose to the front of the mouth
– Tom
Sep 15, 2015 at 3:16
• Personally, I don't really care what Daniel Jones' Xrays are like, but I guess you do. So, then, just look at those Xrays -- whatever they say about the highest point of the tongue, that's where it's at. I can't figure out what you're looking for. Sep 15, 2015 at 3:19
• @GregLee, do you think "X-rays of Daniel Jones" is accurate or not?
– Tom
Sep 15, 2015 at 3:31
• @Tom, yes, I'd guess that it's accurate. This is not the sort of thing academics tend to lie about. Sep 15, 2015 at 3:33

The defined standard for cardinal vowels is the Jones performances. IPA is loosely related to Standard Cardinal Vowels, but the IPA letter < i > can be used for a wide range of phonetic values ranging from Cardinal Vowel 1 to something rather close to [ɪ]. "Accuracy" implies a standard (that is, what thing does the chart accurately reproduce?), and it isn't clear what standard you are interested in. I am inclined to think you mean "correctly reproduces Daniel Jones' tongue positions", but perhaps you mean "accurately reflects the vowels [i,u] etc. in English", or else in Spanish, or maybe Dresden German.

What you would need to do is map the vowel dots in the x-rays to a coordinate system, using some fixed bony structure as a reference point such as the upper incisors and the palatine process). Unfortunately, the "interpretation" graphs don't scale well to the x-rays, though Interpretation 1 is the best of the three (the other two are schematizations, not drawings of x-rays). In the x-rays, the box that surrounds the extreme vowels [i,ɑ] is twice as long horizontally as it is high, but the box that contains the "vowel space" in picture I1 is only 1.25 times as long as it is high. In fact, I1 looks like Peter Ladefoged, and may be accurate as a representation of Peter Ladefoged. However, I1 is only a vowel space: it does not give specific points for vowel locations, so it does not at all represent the 4 tongue positions in the Jones x-rays.

The other drawings are substantially off. So despite the fact that specific vowel positions are not given in I1, the schematized vowel space given there is at least consistent with where specific cardinal vowels are likely to be produced.

• Wiki said "The general principle of the IPA is to provide one letter for each distinctive sound (speech segment), although this practice is not followed if the sound itself is complex." I speak Vietnamese. So does the above sentence mean /i/ in Vietnamese is different from /i/ in English?
– Tom
Oct 8, 2015 at 14:50
• That sentence doesn't mean anything, because sounds being "complex" is an unscientific notion. However, it is certainly consistent with IPA practice to use the same symbol for two distinct phonetic entities. English and Vietnamese vowels are certainly different in terms of tone / phonation. I listened to some recordings of phạm vi, thịt xay, xì mũi, thị trường, bị lừa on Forvo and they sound different from English [i], but that's a fairly uncontrolled sample. I'd say "could be, needs research". Oct 8, 2015 at 16:42

You cannot really project the whole vowel trapeziod into a single picture of the mouth because the shape of the mouth and the tongue actually change as you move through the chart. So any single picture such as the three above will be inaccurate.

The chart really depicts relative positions of the highest position of the tongue with the edges being the extremes thought possible. So any projection will be just a rough schematic suggestion. But 1 is obviously the closest to some semblance of reality.

• Wiki said "The general principle of the IPA is to provide one letter for each distinctive sound (speech segment), although this practice is not followed if the sound itself is complex." I speak Vietnamese. So does the above sentence mean /i/ in Vietnamese is different from /i/ in English?
– Tom
Oct 8, 2015 at 14:50