A reflexive formation is one in which the subject and object of the verb are the same. In English, reflexive pronouns are formed with the suffix “-self” as in “the man washed himself”. Quenya has a similar set of reflexive pronouns from with the prefix im- or in- (VT47/37) that presumably would be used the same way: i atan sove inse.
|1st Person Singular||imni “myself”|
|2nd Person Singular (familiar)||intye “yourself (familiar)”|
|2nd Person Singular (polite)||imle “yourself (polite)”|
|3rd Person Singular||inse “himself, herself”|
|3rd Person Singular (inanimate)||insa “itself”|
|1st Person Plural (inclusive)||imme “ourselves (exclusive)”|
|1st Person Plural (exclusive)||inwe “ourselves (inclusive)”|
|2nd Person Plural||inde “yourselves”|
|3rd Person Plural||inte “themselves”|
This set of pronouns is from the late 1960s. In a somewhat earlier pronominal paradigm from 1964, Tolkien gave a set of reflexive suffixes: -kse along with dual -kset and plural -kser (PE17/75). These suffixes appear in the same row as the “impersonal inflections” used for subject verb agreement, and thus may require (and agreement in number with) an independent subject: i atan sovikse, i atanu sovikset, i atani sovikser.
Conceptual Development: In the Qenya Lexicon of the 1910s, Tolkien gave a “reflexive suffix” ᴱQ. -ko, which he marked with a “?”, appearing beside a variant -to (QL/47). In The Qenya Verb Forms written somewhat later, Tolkien divided Qenya conjugations into Active, Passive and Medial (Reflexive) voice, and the Reflexives used the suffixes -sta or -kto, with masculine, feminine and neuter forms -nko, -kse, -kta (PE14/29). In the Early Quenya Grammar of the 1920s he said:
ending -kto (sg.), -lko (plural) for reflexive accusative, -ktor, -lkor dative (PE14/56).
All of these early reflexives seem to be part of similar paradigms with reflexives based on the suffix -k(t)o, with variants due to phonetic changes or combination with plural of gender indicators.
The 1964 reflexive suffix -kse could be the last iteration of these reflexive suffixes: -ko/-to >> -sta/-kto >> -kto >> -kse. If it is part of this continuum, perhaps -kse = k + se, with k being the ancient reflexive marker (hat tip to Shihali for suggesting this). It is not clear whether -kse could coexist with the im-/in- reflexive pronouns, or were replaced by them.
Neo-Quenya: Most Neo-Quenya writers stick with the late 1960s independent reflexive pronouns in im-, in-. It is conceivable that the suffix -kse (-xe) could coexist with these pronouns, and Thorsten Renk went so far as to suggest (Quentin i Lambe Eldaiva p. 48) that it was a general reflexive marker that could be combined with pronominal suffixes, as in sovixenye “I wash myself” (vs. sovinye imni). Personally I would stick with the better known independent reflexive pronouns, however.