The document lists words containing the letter combination "th" and whether the "th" makes a soft or hard sound. It includes tongue twisters using words with "th".
10. TH: hard sound. This These That Those There Then Other Though Southern Breathe
11. TH: hard sound. Than Worthy Writhe To twist, as in pain, struggle, or embarrassment. Blithe Carefree and lighthearted Northern Thence (= there from) flew to Helsinki and thence to Moscow Therefore They Their Smooth
12. TH: hard sound. Although Thy Archaic of your Gather Lathe Rhythm Bother Father Mother Together Brother
13. TH: hard sound. Feather Further Breathe The Them Mouths Either Neither