The Riekling language is only found in the Dragonborn expansion for Elder Scrolls V. Very little of it is directly translated, so most translations in this dictionary are derived from the names of the dialog topics they're triggered by. In other words, while the general meaning and connotation can be assumed to be accurate, the exact wording is not.
Due to the limited nature of this language, I've listed small phrases as one translation rather than breaking them up into individual words.
agaroo — ??? (said when going from a normal state to suspecting the player is there)
Source: Creation Kit topic name
ah baa faroo — ??? (said when going from normal state into combat)
Source: Creation Kit topic name
alakasee — ??? (said when going from suspecting the player is there back to an unalerted state)
Source: Creation Kit topic name
araa — I'm on it.
Source: Riekling Follower (dialog script notes)
araaaaaaa — ??? (said when detecting a previously escaped player and going back into combat)
Source: Creation Kit topic name
Note: may be a drawn out version of araa above.
araloo — ??? (said when detecting a previously escaped player and going back into combat)
Source: Creation Kit topic name
awafalagahuka — ??? (said when going from a normal state to suspecting the player is there)
Source: Creation Kit topic name
bafagra badee — ??? (said in response to the player giving instructions)
Source: Riekling Follower
bagaru — ??? (said while attacking)
Source: Creation Kit topic name
baaaa roooka — ??? (said when detecting a previously escaped player and going back into combat)
Source: Creation Kit topic name
baroo — what's up (interrogative)
Source: Riekling Follower (dialog script notes)
bek — ??? (said after killing the player)
Source: Creation Kit topic name
bertiflik a goroowala — ??? (part of the chant at the Beast Stone)
Source: Skyrim
boo cah — ??? (said when going from a normal state to suspecting the player is there)
Source: Creation Kit topic name
boo tha — ??? (said when going from normal state into combat)
Source: Creation Kit topic name
brelfik — a word for "hello".
Source: Creation Kit topic name
belifakathoooookawa — a word for "hello".
Source: Creation Kit topic name
boool eekasa — ??? (said when going from suspecting the player is there to attacking them)
Source: Creation Kit topic name
booneetay — a taunt.
Source: Creation Kit topic name
bru char — a phrase for "goodbye".
Source: Creation Kit topic name
bura warag faaanig — ??? (said while attacking)
Source: Creation Kit topic name
buuuuraaaa — ??? (said if they see a nearby Riekling die)
Source: Creation Kit topic name
Note: May be a drawn out version of bura above.
dool — ??? (said after killing the player)
Source: Creation Kit topic name
eeeeloo — ??? (said if they know the player is there, but can't see them)
Source: Creation Kit topic name
Note: sounds similar to "helloooo?"
eerelaya — ??? (said when going from suspecting the player is there back to an unalerted state)
Source: Creation Kit topic name
faaa rawala — ??? (said in response to the player parting ways with the follower)
Source: Riekling Follower
Note: sounds similar to "farewell".
faa thoo — ??? (said when going from combat to loosing sight of the player)
Source: Creation Kit topic name
falagara — ??? (said while attacking)
Source: Creation Kit topic name
farwag — a word for "goodbye".
Source: Creation Kit topic name
feeerako — ??? (said when going from suspecting the player is there back to an unalerted state)
Source: Creation Kit topic name
felgir paw tuwani barj — ??? (said by the chief as he addresses his warriors about attacking their Nord enemies)
Source: Riekling Chief
foo may wa — ??? (said when detecting a previously escaped player and going back into combat)
Source: Creation Kit topic name
foora paka — ??? (said when going from suspecting the player is there back to an unalerted state)
Source: Creation Kit topic name
froo ha cawasy jo la — ??? (said by the chief as he addresses his warriors about attacking their Nord enemies)
Source: Riekling Chief
gelfek — a word for "goodbye".
Source: Creation Kit topic name
goora — ??? (an exclamation, likely encouraging)
Source: Skyrim
habichaaalakawaramalek — ??? (said in response to the player asking to trade)
Source: Riekling Follower
hafahoo — ??? (said in response to the player initiating a favor)
Source: Riekling Follower
hagajawala — a taunt.
Source: Creation Kit topic name
hawah — ??? (an exclamation, likely affirmative)
Source: Riekling Chief
hoo jah — ??? (said in response to the player saying they don't need a favor after all, maybe similar to "all right" or "as you wish".)
Source: Riekling Follower
hoola wakasee — ??? (said when going from suspecting the player is there back to an unalerted state)
Source: Creation Kit topic name
hooojarakwafala — a taunt.
Source: Creation Kit topic name
hra woong aba — ??? (part of the chant at the Beast Stone)
Source: Skyrim
hrawwaaaa — a word for "hello".
Source: Creation Kit topic name
hufwah — ??? (said while attacking)
Source: Creation Kit topic name
huuwa — ??? (said if they know the player is there, but can't see them)
Source: Creation Kit topic name
joo fah — no way.
Source: Riekling Follower (dialog script notes)
kaaarooo — ??? (said when going from combat to loosing sight of the player)
Source: Creation Kit topic name
Note: may be a drawn out version of karoo.
karoo taray pelfrik — ??? (said by the chief as he addresses his warriors about attacking their Nord enemies)
Source: Riekling Chief
kalafoo — ??? (said when going from suspecting the player is there to attacking them)
Source: Creation Kit topic name
kalaree — ??? (said if they know the player is there but don't see them)
Source: Creation Kit topic name
kawafoo — whatever (dismissive).
Source: Riekling Follower (dialog script notes)
keeel fa — ??? (said after killing the player)
Source: Creation Kit topic name
koolawasa — ??? (said when going from normal state into combat)
Source: Creation Kit topic name
koowah — a taunt.
Source: Creation Kit topic name
kooova mook — ??? (said when going from suspecting the player is there back to an unalerted state)
Source: Creation Kit topic name
meeeelaaak — ??? (said when going from combat to loosing sight of the player)
Source: Creation Kit topic name
mella kalee — ??? (said when going from knowing the player is there to assuming they've left)
Source: Creation Kit topic name
moooong cha — ??? (said when going from suspecting the player is there to attacking them)
Source: Creation Kit topic name
muuuu fa — ??? (said if they know the player is there, but can't see them)
Source: Creation Kit topic name
muwafathoo — a word for "hello".
Source: Creation Kit topic name
peeeeee fa — ??? (said when detecting a previously escaped player and going back into combat)
Source: Creation Kit topic name
poo ma — ??? (said if they know the player is there but don't see them)
Source: Creation Kit topic name
raaa fay — ??? (said when going from knowing the player is there to assuming they've left)
Source: Creation Kit topic name
roo cha — ??? (said by the chief as he gathers the warriors to attack their Nord enemies)
Source: Riekling Chief
takafala gajoo — ??? (said in response to the player asking them to do something)
Source: Riekling Follower
tika twafaara filik — ??? (part of the chant at the Beast Stone)
Source: Skyrim
tiri fuklik taaar aburak — ??? (part of the chant at the Beast Stone)
Source: Skyrim
wafoo athaaaal — ??? (part of the chant at the Beast Stone)
Source: Skyrim
wilberk tikflaaar — ??? (said while attacking)
Source: Creation Kit topic name
waayaruu — ??? (said if they know the player is there but don't see them)
Source: Creation Kit topic name
Note: sounds similar to "where are you?"
wuuuuuupaaaaa — ??? (said if they see a nearby Riekling die)
Source: Creation Kit topic name
yuchaaa tungar cha tiweki — ??? (said while attacking)
Source: Creation Kit topic name
yuntar — a word for "goodbye".
Source: Creation Kit topic name