There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.

Qenya 

ista-

verb. to know, learn

Qenya [Ety/IS; PE22/104; PE22/106; PE22/107; PE22/108; PE22/109; PE22/111; PE22/112; PE22/114; PE22/115; PE23/076; PE23/077; PE23/083; PE23/085; PE23/099; PE23/108] Group: Eldamo. Published by

ista

noun. knowledge

istya

noun. knowledge

Qenya [Ety/IS; PE21/12; PE21/13; PE22/020] Group: Eldamo. Published by

istare

noun. knowledge

issa

pronoun. *their (emphatic possessive other)

Qenya [PE23/078; PE23/079] Group: Eldamo. Published by

malli yēni ista/ekēnie túro

how many years knows/has Túro seen

nila ista má

I know not what

Qenya [PE23/099; PE23/102] Group: Eldamo. Published by

Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.