Yeah in Japanese a few consonant sounds like ‘r’ and ‘l’ sounds or ‘h’/‘f’ or ‘s’/‘th’ or ‘z’/‘ð’ are basically heard as the same (an American ‘r’ might even sound like a weird ‘w’ to Japanese), and English has around 17 to 24 distinctive vowel sounds generally (based on quality) while Japanese has 5 plus vowel length and tones (pitch accent). As a result of the phonetic differences between the languages, it can be hard to hear or recreate the differences in sound quality (especially when it’s Japanese on the speaking/listening end, but Americans also sure have a terrible time trying to make Japanese sounds like the “n” or “r” or “ch”/“j” or “sh”/“zh” or “f” or “u”. they just perceive it as the same as the closest sounds in English)

In my experience, only God can hear the difference between Polish “dż” and “dź” / “cz” and “ć” (and the others)…