Error 0x8004507A

Value: -2147200902 | 0x8004507A | 2147766394

What does it mean ?

SPERR_UNSUPPORTED_PHONEME  
Unknown phoneme
Value: 20602 | 0x507A | 0b0101000001111010

Where does it come from ?

FACILITY_ITF  
COM/OLE Interface management. FACILITY_ITF is designated for user-defined error codes returned from interface methods
Value: 4 | 0x004 | 0b00000100

StackOverflow

Other Errors for FACILITY_ITF