Do orcs from different parts of Middle-Earth all speak the black speech? In the Lord of the Rings films, the orcs are shown to speak in the common tongue. Even those from Mordor.But in The Hobbit, Azog and others only know the black speech.
From Lord of the Rings Appendix F:
And these creatures, being filled with malice, hating even their own kind, quickly developed as many barbarous dialects as there were groups or settlements of their race, so that their Orkish speech was of little use to them in intercourse between different tribes.
So it was that in the Third Age Orcs used for communication between breed and breed the Westron tongue...
There is therefore no single Orkish language.
The situation in the LotR movies is consistent with this, because - if you check the movie scenes again - you'll see that for the most part the Orcs depicted are from different tribes; for example (from The Uruk-Hai):
To Pippin's surprise he found that much of the talk was intelligible; many of the Orcs were using ordinary language. Apparently the members of two or three quite different tribes were present, and they could not understand one another's orc-speech.
It's therefore correct that they use the common speech when dealing with each other.
In the Hobbit movies however the majority of Orcs depicted are from Dol Guldur, and so it's also consistent that they would all use the same language.
Regarding the Black Speech, that is a separate language to Orkish dialects and has a different origin. Again we refer to Appendix F:
It is said that the Black Speech was devised by Sauron in the Dark Years, and that he desired to make it the language of all those that served him, but he failed in that purpose. From the Black Speech, however, were derived many of the words that were in the Third Age wide-spread among the Orcs, such as ghâsh 'fire', but after the first overthrow of Sauron this language in its ancient form was forgotten by all but the Nazgûl. When Sauron arose again, it became once more the language of Barad-dûr and of the captains of Mordor.
Orkish languages can therefore be said to have had some influence from the Black Speech, but we can confidently state that Orcs (in general) do not speak the Black Speech, and the Black Speech is not Orkish.