When Phelps is placed in a cell as a ruse, he effects a British accent when conversing with El Kabir. But prior to that and afterwards, he spoke in plain English.
When Barney is pouring the nitroglycerine into the bottle you can hear it splashing as it falls. Nitroglycerine is unstable, especially when warm and doing it this way would result in an explosion. The only semi-safe way would be to tilt the bottle and let the nitro slide down the wall of the bottle.
The nitroglycerine, stored on dry ice, appears as a liquid, and Barney is able to pour it into plastic tubes. However, nitroglycerine freezes at 57°F (14°C) and would certainly be solid at the extreme cold temperatures provided by dry ice.
When the team go into the cave Barney clearly has an electric drill with him but no generator for a power supply and also the drill bit is about 5 or 6 inches long but yet he manages to insert a couple of feet of tubing into the wall for the nitro.
When Barney's fake ID card is shown to the camera, it shows his name as Ahmed Mahal and his rank as "Sargent". If a Middle Eastern army is obligingly going to print its ID cards in English rather than Arabic, they'd be sure to spell it correctly.