Appendix:Navajo roots and stems derivation

Introduction
This appendix proposes an analysis of the patterns in which stems derive from roots. While comparison with other Athabaskan languages or knowledge in the Proto-Athabaskan reconstruction efforts may prove vital to a deeper understanding of the mechanisms at stake, it is not the goal of this analysis, which has a more statistical / synchronic focus.

For the purpose of this study, only the momentaneous aspect, the most pervasive of all, will be considered.

The root is conventionally represented by its momentaneous perfective stem, as it is the most conservative of all stems and preserves many of the root's original features (one exception is for closed short roots where original tone is neutralized, see below).

Restrictions on tone, length and openness

 * 1) Short closed syllables are always low-tone (tone is neutralized).
 * 2) Open syllables must be closed by a glottal stop, except for high-tone short syllables.

Note: There are very few exceptions to these general principles: cha, zo, yaa/laa.

Restrictions on vowel quality

 * 1) e in short fully-closed syllables never occurs and raises to i: *kes > kis
 * 2) In roots with historically labialized onset or coda, short vowels are limited to o and i: *kʷes > kos.

Root types
Stem derivation is primarily dependent on the root's coda. Five types of roots can be distinguished:
 * 1) Open roots (∅-type)
 * Historically ended in a vowel or diphthong, open roots are today either open (if short and high) or closed by a glottal stop. Sometimes a nasal (-v̨) suffix appears in the perfective only.
 * 1) Nasal roots
 * Historically ended in a nasal, these roots end today in a nasal vowel. Sometimes a dental suffix (-d) appears in the perfective. Also, in some occurrences, the vowel didn't nasalize and a consonantal -n survived.
 * 1) Quasi-open roots (K-type)
 * Historically ended in a velar or uvular, quasi-open roots typically end in a glottal stop (not to be confused with the purely phonotactical glottal stop of open roots), or in the diphthong -ai (when the velar was palatalized).
 * 1) Dental-closed roots (D-type)
 * Historically ended in a dental, these roots end today in -d, which also lenites to a glottal stop in the iterative stems.
 * 1) Fricative-closed (S-type)
 * These roots end in -z, -zh, or -l. They typically devoice in stems other than perfective.

Stem permissible shapes
The table below shows what shapes a stem can take depending on the root type and the mode. Only tone, length, and coda are considered here. Actual quality of the vowel, which may be affected by labialization, ablaut, or shortening, is not addressed.

The possible shapes of the optative for the open and nasal roots are by far the most difficult to delimit, even more so to predict based on synchronic data.

Roots and stems table
Deriving imperfective stems from perfective ones is sometimes fuzzy. For example, while has imperfective stem with a low tone (-ch’iish),  with a similar rhyme, has a high-tone imperfective (-zhíísh).