Laptop keyboards have less key travel which may feels like it will register the keys faster than a seperate keyboard. But that is not the case both the laptop and normal keyboard may register keys at same speed despite of the key travel or if there is a difference due to brands the difference will no be much that it would affect your typing speed a lot.
There are other espects that makes both different, that may eventually can affect your typing speed that we are going to discuss in broad.
Ergonics
A laptop keyboard fits on the laptop bottom surface and because a laptop is a portable device so the keyboard stays flat over the bottom surface and shares the space with the mouse pad, this creates a ergonic issue for many users. This ergonomic reason can make your wrists unconfortable to rest for a long typing session.
On a normal keyboard, the keyboard stays at a height which already provides a ergonomic benefit to a seperate keyboards. Many keyboards also provides different levels of slope (angle) adjustments that users can switch to according to their preferences which may enhance the comfort of your hands and wrists while typing.