/θ/ — choose the word that contains the sound represented by the given phonetic symbol

Analyze the question: You need the word that contains the voiceless dental fricative /θ/ (the "th" in think, thin). Be careful, because "th" can also be pronounced /ð/ (as in this, the).

Concept:

• /θ/ is voiceless. Your vocal cords do not vibrate (e.g. thin, bath, teeth).
• /ð/ is voiced. Your vocal cords vibrate (e.g. then, mother, breathe).

Check each option:

• A. teeth: /tiːθ/. It ends with the voiceless /θ/. ✔
• B. tough: /tʌf/. The "gh" is pronounced /f/, so there is no /θ/. ✘
• C. northern: /ˈnɔːðən/. The "th" is voiced /ð/. ✘
• D. worthy: /ˈwɜːði/. The "th" is voiced /ð/. ✘

Answer: A. teeth

Tip: Put your fingers on your throat while saying the "th" sound. If you feel a buzz, it is /ð/. If you feel no vibration, it is /θ/. Also, "th" in the middle of a word with an "-er", "-y" or "-ern" ending is often voiced (northern, worthy, other), while "th" at the end of a noun is often voiceless (teeth, mouth, path).