I accidentally hit my thumb with a hammer.
[aɪ ˌæksəˈdɛntl̩i ˈhɪt ˈmaɪ ˈθəm ˈwɪθ ə ˈhæmər.]
My thumbs hurt from texting all day.
[ˈmaɪ ˈθəmz ˈhɜrt frəm ˈtɛkstɪŋ ˈɔl ˈdeɪ.]
Why is your thumb wrapped in a plaster?
[ˈwaɪ ˈɪz jɔr ˈθəm ˈræpt ˈɪn ə ˈplæstər?]
"thumb" is in the lesson "Body parts 2" (Level 25), along with 8 other useful words. LinDuo has 180 topic lessons like this one, 2,375 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.