Just to clarify If we go by the historical classification we have the following declension classes for strong nouns Masculine A wa ia ja i and u stems plus a few relics of consonant stems Feminine w j i and i stems plus a few irregularities leftovers from the consonant classes and the word h nd which is the sole feminine survivor of the u class Neutral A wa ia and ja stems plus the relic f u class Those are all declension classes The weak nouns then have a system of their own I hope this answered the question Regarding the article when and how it is suffixed is another chapter All the best