First

The language spoken by the Mapuche people both in Argentina and Chile is called Mapuzugun: /mapuθu'ŋun/ or Mapudungun /mapuθu'ŋun/) (from "mapu" = land and "zugun" /θu'ɲun/ = speech") and it is still basically a spoken language despite several efforts to achieve a unified writing system.
There is no academy or literary society acting as a regulatory body for the language. Mapuzugun will heavily relay on oral tradition to transmit history, literature, law and other knowledge across generations until a writing system is agreed upon. Certain institutions that have tried to normalize the language have received huge criticism on both sides of the Andes: Puelmapu (from "puel" /puel/ = East) and Gulumapu ("Gulu" /'ɲulu/= west).
There are three known writing systems and each community (or lof) usually adopts one based on the community's decision.
I will keep aside all political and ideological views, but need to decide on which system I will use for this blog: I will use the Ranguileo Graphemic Writing System (or Grafemario Ranguileo in Spanish) that is widely accepted by most communities in Puelmapu.
Although there are many references about stress patterns in Mapuzugun, regional variations of the language usually include stress variations and the correct stressed syllable will depend on the region one has acquired a specific vocabulary.
I found very interesting the fact that stress actually does not affect the understanding among people fluent with the language (and this has been my experience, too!)
Local variations or dialects are normally accepted as the spoken language of each region and none is considered to have a better or higher status than the other. I have experienced that the usual question when people speak Mapuzugun is that they routinely ask each other "how do you say this in your region?". Regional variations do not seem to prevent people from understanding each other.
For example, the interrogative pronoun "iney" (who?) can be "iñi" /i'ŋi/ depending on the region. Usually both versions are taught.
Also, there is a tendency to replace Mapuzugun so-called 6th vowel by the vowel "i". The 6th vowel is spelled v, ï or ü depending on the writing system.
The sound of the 6th vowel depends on whether it is stressed or not:
When stressed, it is a high back unrounded vowel [1] represented by /ɯ/ using the International Phonetic Alphabet (e.g. Scottish Gaelic's word for "strait" caol /kɯːl/), although other bibliography describes this as high central unrounded vowel and represented by the API symbol /ɨ/, e.g. as "e" in roses /'ɹoʊzɨz/
When unstressed, it is a mid central unrounded vowel , represented by the API symbol /ə/.

Other regional variations include variations in the consonants (e.g. the word for cat is both "narki" /'narki/ or "ñarki" /'ŋarki/)

In my next entry I will describe the Ranguileo Graphemic Writing System and compare it to the "Unified Mapuche Alphabet" mostly used in Gulumapu.
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[1] Cañumil, Tulio et al, Descripción de la lengua Mapuche - Mapucezugun Ñi Cumgeel, Agrupación Mapuche Wixaleyiñ, Florencio Varela, Buenos Aires, Puelmapu.

Note: unless otherwise stated, I will use the bibliography available from my language school and other papers provided by Tulio Cañumil. Also, I will use my notes taken during the lessons.