Matrūk al-tasmiyah ʿāmidan
An animal slaughtered with deliberate omission of the divine name.
Matrūk al-tasmiyah nāsiyan
An animal slaughtered while the slaughterer forgot to mention the name.
Hanafi reasoning distinguishes the two. A deliberate omission is treated as prohibited, while an omission through forgetfulness has a different legal consequence because forgetfulness is recognized as an excuse.
Therefore the analysis does not stop at whether the words were pronounced. Why they were omitted can also affect the ruling.