Dictionary uses IPA to depict the sound. However, most of them do not include diacritics, and thus it is very hard for learner to distinguish the sound.
See this quote from Wiki
IPA symbols are composed of one or more elements of two basic types, letters and diacritics. For example, the sound of the English letter ⟨t⟩ may be transcribed in IPA with a single letter, [t], or with a letter plus diacritics, [t̺ʰ], depending on how precise one wishes to be.[note 2] Often, slashes are used to signal broad or phonemic transcription; thus, /t/ is less specific than, and could refer to, either [t̺ʰ] or [t], depending on the context and language.
For example, see this word "Thai"
/taɪ/ in http://dictionary.cambridge.org/dictionary/english/thai
I think it should be depicted as
t generates quite a lot of air.
So, Do we have any English dictionary that shows precisely both letters and diacritics?