It is correct that the word 'later' on it's own would be pronounced as /ˈleɪtə/ or 'laytuh', however in a sentence you will hear the 'r' because the sound runs on to the next word for fluency. For example 'later on..' spoken quickly might sound like 'laytuh ron' so as you say, when you listen to native speakers you will hear it. For this reason in some dictionaries the phonetic spelling will be written as /ˈleɪtə(r)/ because depending on the context sometimes you will hear the 'r' and other times you won't. I hope that makes sense! Clemency

Hi Tomo, Sorry to say this: the IPA of any word only shows one regional accent, and a very rough version. So don't take it as "perfectly accurate", but only a rough approximation. The "r" at the end of a syllable can sound vastly different between accents. What you read in the dictionary seems to be one commonly-accepted UK pronunciation. I'm not sure what you meant by "native speaker", but a US speaker (for example) tends to pronounce every single r, but certain British and Australian accents will even drop it entirely. No matter what we do, none of us have a problem understanding it. ;)