Or more likely, the original was meant to be: — which is nonsense.
"thmyl" → "lymht" "fylm" → "mlyf" "alans" → "snala" "walnms" → "smnlaw" "rb" → "br" "syd" → "dys" thmyl fylm alans walnms rb syd
— which could be interpreted as:
"thmyl" → "lymht" (not clear) But more likely it's a simple shift cipher or each word reversed individually: Or more likely, the original was meant to
Given the lack of clear decryption, but the phrase looks like it might be a playful scramble of a common phrase. One possibility: it's an accidental keyboard shift? Or simply nonsense. Or more likely
But perhaps it's a simple substitution cipher with shift of +1: t→u, h→i, m→n, y→z, l→m → "u i n z m" — no.