Comment by somat

I know Japanese does not have a th sound, and I don't think chinese or most other asian languages have it, but am less sure about that. Unfortunately I lack the data needed to substantiate my claim.

    with
    lang_sounds as (
    select
        lang,
        unnest(string_to_array(ipa, null) ) as sound
    from world_dictionary
    ),
    totals as (
    select
        lang,
        count(sound) as sound_count
    from lang_sounds
    group by lang
    )

    select
        lang,
        totals.sound,
        count(sound) / totals.sound_count
    from
        lang_sounds join
        totals on
        lang_sounds.lang = totals.lang
    where sound = 'θ' or sound = 'ð' or sound = 'θ̠' or sound = 'z'
    group by lang, sound
    order by count(sound) / totals.sound_count