Grammar checkers are considered as a type of foreign language writing aid which non-native speakers can use to proofread their writings as such programs endeavor to identify syntactical errors.[10] However, as with other computerized writing aids such as spell checkers, popular grammar checkers are often criticized when they fail to spot errors and incorrectly flag correct text as erroneous. The linguist Geoffrey K. Pullum has argued that they are generally so inaccurate as to do more harm than good: "for the most part, accepting the advice of a computer grammar checker on your prose will make it much worse, sometimes hilariously incoherent."[11]