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Yes-no questions have a rising intonation in many languages, some of which have a question marker in addition, like Chinese ma 吗. In Tunisian, this rising intonation is accompanied by an interesting marker: a vowel added to the sentence, as you can hear below: “ftart-ǝ?” 
To say “did you eat?” the person asks “ftart-ǝ?” not “ftart?” w/ just the rising intonation. The vowel is v important to get the question meaning–the intonation alone is awkward–just like 吗 in Chinese (and it doesn’t co-occur w/ wh-words). 2/6
The difference tho is that 吗 is not transferred to English for L2 speakers, but a Tunisian speaking Eng. might say sth like “did you eat-ǝ?” In this spectrogram, you can see the intonation accompanied by the vowel in the Eng. question "do you want some food?" 3/6
This is p cool bc other question markers don’t transfer like that. For ex, Tunisian has a suffix -ši that does the same job as this vowel ftart-ši?/ftart-ǝ? = “did you eat?” L2 speakers might say “did you eat-ǝ?” but not “did you eat-ši?” 4/6
This makes sense since the vowel is the carrier of the question intonation, and felt as an important part of the question, but it’s not a full on “word,” so it’s easily transferrable alongside the intonation, and we (Tunisians) aren't really aware of it when we speak. 5/6
I think it’s specific to Tunisian, but if any other languages (Arabic or otherwise) have this, lmk! If you wanna read more about this, check this paper by N. Bouchhioua, S. Hellmuth & R. Almbark 
https://books.openedition.org/iremam/3961?lang=en –this is where the spectrogram above is from. 6/6
https://books.openedition.org/iremam/3961?lang=en –this is where the spectrogram above is from. 6/6
