idioglossia /id-i-ō-glosˈi-ə/

1. A condition in which pronunciation is so bad as to be quite unintelligible
2. A private language developed between two or more children, esp twins, etc

• interferon
• interferons
• interfertile
• interfile
• interfiled
• interfiles
• interfiling
• interflow
• interflowed
• interflowing
• interflows
• interfluence
• interfluences
• interfluent
• interfluous
• interfluve
• interfluvial
• interfold
• interfolded
• interfolding
• interfolds
• interfoliate
• interfoliated
• interfoliates
• interfoliating