孩童母音發展的兩個議題：(a)孩童的年齡增長，是否會帶來母音基頻（F0）與共振峰（F1, F2, F3）的下降？(b)男女孩童的母音區分始於哪個年齡層？本研究為此延請了140位6歲到12歲的美濃客家孩童，請他們讀包含6個母音[i、e、a、u、o、i]的字表，再透過Praat的分析。結果顯示：(a)並非所有的年齡層都呈現母音共振峰會因年齡的增長而降低。在10-11歲之前，共振峰的頻率值高低各有區別。(b)男孩在11歲，女孩在10歲之後，母音呈現年齡增長共振峰降低的趨勢。(c)女孩子要等到11歲後，母音共振峰才穩定地比男孩母音的共振峰還要高。

In the literature of child development remain two issues: (a) Is it true that when children get older, the vowel formants (F0,F1, F2, F3) are on the decline? (b) At what age female subjects begin to have higher vowel formants than male? We invited 140 children for a list of six Hakka vowels, formants extracted. The final results are: (a) Not all vowel formants fall when age increases, in particular, before 10 or 11, much rise and fall being observed. (b) The theory of formants falling with age increasing is on the right track, at least, after 11. (c) Gender difference begins to show up at 7 or 8. However, it is not until 11 that the movement begins to be stable.