The answer is: Not really!!!
It is very easy for Vietnamese but not so much for foreigners as a certain mastery of Vietnamese is needed to take the drivers. In Vietnam, Grab offers Grab Bike service which is cheaper than Grab Car because bikes/motorcycles are the most popular vehicle in Vietnam. It is useful to have addresses and a few translated phrases written down to show the driver. It is also advisable to set your pick-up location to spots with Wi-Fi/3G signals. When you book a Grab bike, the driver often calls via your phone number provided to confirm the pick-up location
Here are some sample texts that may come in handy:
Tôi không biết Tiếng Việt: I don’t speak Vietnamese
Tôi đang ở.... : I am standing in...
Credit to Chrisgel Ryan Cruz
A tip for you: You can look around and ask a local to help you (to communicate to the Grab driver in your phone). Most people would understand and be happy to help.