Syllabification is the task of breaking words into syllables. 

Syllabification 

A syllable consists of consonants and vowels. For example, the word “dog” is a single syllable, and the word “catnip” has two syllables. 

If a syllable starts with a consonant, then that consonant is called the onset.

The core vowel is called the nucleus. 

If there’s any consonant following a nucleus, it’s called a coda.

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Vowels are the sounds you make when there’s less obstruction of airflow coming out from your lung. Vowels are mainly voices. Examples include \[ae\], \[au\], \[ow\] and others.

Vowels

An on-going but a helpful book resource about NLP
https://web.stanford.edu/~jurafsky/slp3/

Speech and Language Processing (3rd ed. draft) 

Different from the way we characterize consonants, there are 3 most important characteristics of a vowel:

•	Vowel height, which is roughly the height of highest part of the tongue.

•	Vowel frontness and backness, which represent whether the tongue raise forwards or backwords.

•	Roundness of lips when a vowel is pronounced.


Characteristic of Vowels

Syllables

A long vowel is a vowel that is pronounced for a significant period, usually about twice as long as a short vowel. 

Long Vowel

A vowel shift is a "systematic sound change in the pronunciation of the vowel sounds of a language"

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