Which is the correct sentence?

Neither is correct. Both should contain " . . . for a tuition teacher." The first sentence would sound awkward to a native-speaker, and the second sounds more natural, with the correction noted above. Also in both sentences, for the written word, one would write "speaker's"--note the placement of the single quote mark (inverted comma). That is because by placing the definite article before "native speaker" you have made it a singular, modified noun.

Many thanks, Setanta, for your explanation as well as correction.