Re: Root-Role System

Forgot to mention-- your system is not unlike Indonesian/Malay--

basic root /ajar/ (historically seems to have meant 'trained'*)
bel+ajar (< ber+ajar) to study; to learn (~to engage in 'ajar')
meng-ajar to teach (something) (active vb), also--
meng-ajar-kan (caus.) specifically, teach s.t.
mem-pel-ajar-i specifically, to teach (someone) (-pel- > /per/)
pel-ajar (< per+ajar) student
pel-ajar-an (< per+ajar+an) lesson
peng-ajar teacher
ajar-an teachings, dogma, theory etc.

Lots of base-words can have these, and other, derivations.
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*In Ml/Indo. this bare root only occurs, AFAIK, in the insulting expression
"kurang ['less, not very'] ajar" = impolite, ill-brought-up, uneducated.
Rather like, IIRC, Russian "ne kulturni" (sp?)

Also, interestingly, in some languages the word for "horse" is derived:
*ajar-an ~'the trained one'.