To become a native speaker, beyond obligatory rules, children need to learn systematic variation in the language, as it is present at all levels of language structure and is an integral part of linguistic knowledge. To give an example in English, speakers sometimes pronounce words ending in -ing with -in' (e.g., working vs. workin') depending on…

The idea that vowel nuclei in many northern European languages can be divided into peripheral and non-peripheral categories is discussed. Peripheral vowels are those located at the edge of the vowel envelope, and non-peripheral nuclei are those located on the inside. This assertion has not received as much scrutiny as it should. There are at least…