inarticulacy       
noun [ U ] uk/ˌɪn.ɑːˈtɪk.jə.lə.si/ us/ˌɪn.ɑːrˈtɪk.jə.lə.si/ (also inarticulateness, uk/ˌɪn.ɑːˈtɪk.jə.lət.nəs/ us/ˌɪn.ɑːrˈtɪk.jə.lət.nəs/)
 不善辞令,口齿不清
the state of being unable to express feelings or ideas clearly, or of being expressed in a way that is difficult to understand
  His inarticulacy is taken for stupidity.  他的口齿不清被认为是愚蠢所致。 
 Some people believe this inarticulacy is intentional. 有些人认为这种口齿不清是故意的。 
 See: inarticulate
 - More examples
- Inarticulacy leads to an inability to communicate.
- Inarticulacy seemed to become a political asset.
- You would think that his inarticulacy and lack of social graces would exile him from polite society.
- I was appalled by the inarticulacy of the message.