The correct phrase is:
Ash hadu an la ilaha illal lah
It should be pronounced correctly. As it is something to do with listening, I suggest you double check it with resident alim.
In regards to your second query, I assume this ruling would help you to understand the ruling:
943. Adhan and Iqamah should be pronounced in correct Arabic. Hence, if they are pronounced in incorrect Arabic, or one letter is uttered for another, or if, for example, its translation is pronounced, it will not be valid.