[1] An example from the history of English is the lengthening of vowels that happened when the voiceless velar fricative /x/ and its palatal allophone [ç][2] were lost from the language.
E.g. (using the Hebrew definite article [hey with pataḥ plus dagesh in following consonant]):[3] Compensatory lengthening is very common in Ancient Greek.
In the second stage, the first consonant of the cluster or geminate was lost, which was accompanied by the lengthening of that vowel and sometimes additional nasalization.
[7] The voiced velar fricative (/ɣ/), has undergone a sound change in Turkish by which the consonant was completely lost and compensatory lengthening of the preceding vowel occurred.
In modern Turkish, Ğ is used either as a silent letter indicating a syllable break or as a vowel lengthener for the preceding sound.