Why we are saying "uh" less and 'um' more

What's in an "um"? According to experts, "uh" and "um" are somewhat different beasts. "It does seem to be the case that 'um' generally signals a longer or more important pause than 'uh'," says Mark Liberman, a linguist at the University of Pennsylvania. At least that's what he thought. Liberman has been studying these so-called "filled pauses" for almost a decade, and he has made a rather curious

[daybeforeyesterday]

うーむ

[godmother]

“有声休止”で、３歳近い子供のことを思い出している。言葉に詰まったりした時、有声休止は使っていないと記憶。年齢が増すごとなのか？心理的にも面白い変化だと思う。