Is there a rule to identify which is the correct pronunciation for words with -th- spelling (mother- think), this /θ/ or this /ð/?

  • 3
    and then there's foothill
    – Jim
    Commented Apr 1, 2013 at 4:39

2 Answers 2


As Matt says, there are no strict rules. However, there are patterns:

  • word-initial is usually /θ/ (thin, think) except in function words (this)
  • word-medial is usually /ð/ in native vocabulary (mother) and /θ/ in loanwords (Athens)
  • word-final is usually /ð/ in verbs (breathe) and /θ/ in nouns (breath).
  • 1
    RE: the first bullet, how do you define a function word? Commented May 16, 2013 at 15:46
  • 3
    It's easier to list examples than to give a rigorous definition: than that the thee their theirs them themselves then there these they thine this those thou though thus thy thyself
    – user230
    Commented May 16, 2013 at 15:50

No. There is no rule - as "th" can become either /θ/ or /ð/ depending on the word:

thin /θɪn/

this /ðɪs/

mother /mʌðər/

think /θɪŋk/

On the plus side, the audible difference between /θ/ and /ð/ is so small that normally when speaking getting them mixed up will go unnoticed.


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