Complex sentence: In the 1970's an orthography was created which uses double vowel letters to represent long vowels; and because of the ambiguity that would occur if the glottal stop was not written, the glottal stop was written with the letter' q'.
Split into simpler sentences: In the 1970's an orthography was created which uses double vowel letters to represent long vowels. Because of the ambiguity that would occur if glottal stop was not written, glottal stop was written with the letter' q'.