The contact between languages consolidated the opposition of the long and short vowels.

语言间的接触强化了元音长短音的对立，导致长短元音最终确立。

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Your child will learn to combine sound combinations for the short and long vowels for a, e, i, o, and u along with other special phonics sounds.

本课中，您的孩子将会学习如何组合各种长短音，元音及特殊音素的发声。

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The appearance of the tones allowed the lax and tense vowels more freedom, and then the long and short vowels came into being.

声调的产生反过来又促使松紧元音进一步松化，出现了元音长短音的萌芽。

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