From time to time I feel compelled to decry the declining state of the English language. For those who wonder why people like me care about grammar, it’s because it’s important for several reasons. Bad grammar leads to misunderstanding. This can be, and usually is, trivial, but at times can be dangerous, even lethal.

Recently I heard a news report of the investigation of the AirAsia crash over the Java Sea. While trying to correct from a stall, the pilot, a non-native English speaker, yelled to the co-pilot to “pull down” on his stick. The co-pilot, a native French speaker, understood the word “pull” to mean pull up, which he did, resulting in the crash. The normal instructions are to push down or pull up. The pilot’s instruction conflated the two. This is a contradiction ambiguity. One of the funniest television comedies ever, Twenty Twelve, had a running gag where Hugh Bonneville’s wishy-washy character responds to every suggestion or complaint with “Yes, no, absolutely.”

More common forms of ambiguity are syntactic and semantic ambiguity.¬†Semantic ambiguity involves using a word or phrase with more than one meaning. I remember my high school English teacher’s favorite example of semantic ambiguity: “A case of beer was mysteriously left on the front step of the police station. The chief is working on the case.” A well-known one used humorously is “The peasants are revolting.” In these examples, the words “case” and “revolting” can have more than one meaning.

Syntactic ambiguity is where the sentence structure creates the confusion.¬† For example, “The horse raced past the barn fell.” The reader could think the speaker means “The horse raced past; the barn fell.” The correct reading is “The horse (that was) raced past the barn fell.” Since the word “fell” is also a British dialect word for a field or moor, a semantic ambiguity is also present, where the reader thinks the horse raced past a field referred to as the barn fell. Headlines, due to their shortened structure, often exemplify this type of ambiguity, e.g. “Squad Helps Dog Bite Victim.

However, the most frequent syntactic ambiguity in my experience in everyday speech is the dependent clause placed at the beginning of a sentence. For example, “Because of their inherently dangerous nature, commercial passenger aircraft are not permitted to carry lithium batteries.” Dependent clauses at the beginning of a sentence should refer to the subject that immediately follows, not the predicate, but people say this wrong all the time. Here the word dangerous is probably meant to refer to the batteries, but aircraft are inherently dangerous, too. I hear news reporters screw this up constantly. “Like any corrupt official, the mayor wants the police chief replaced.” The reporter is actually characterizing the mayor as corrupt, not the police chief, although she probably means the opposite. This ambiguity can be easily eliminated by placing the clause at the end of the sentence where it is closer to the thing it modifies.

Yet another form of semantic ambiguity is the wrong word or malapropism. It’s not a word with two meanings; it’s when the speaker uses a similar word with a different meaning. The term malapropism is named after Mrs. Malaprop, a scatterbrained character in Sheridan’s play The Rivals. A real-life example I recall from law school was the sign on a building on Telegraph Avenue that read “Stationary department has moved.” As written, it’s an oxymoron as well. Stationary things don’t move. They meant, of course, the stationery department. In fact this might be a fair description of what happened with the AirAsia flight. If the pilot’s native language did not have words with the exact meanings of push and pull in English, the word “pull” to him might have been equivalent to something in his native language that meant something like “move [something] with your hand” but not necessarily towards you.

So please be careful in how you phrase things, whether in writing or speaking, especially when giving instructions. Geocachers, reread those cache descriptions and logs before you post them. Think about whether someone could misinterpret what you said. “It’s on the left side.” Really? And that’s if you’re walking north or south on the trail?