Today, we'll practice one of the trickiest sounds in English: the TH sound. Actually, English has two TH sounds: The voiceless /θ/, like in think, thank, thirty. The voiced /ð/, like in this, that, brother. Many students replace them with t, d, s, or z. For example: They say tank you instead of thank you. Or zis instead of this. Get the transcript on my website: