Original sentence: Mass-classifiers are present in all languages since they are the only way to "count" mass nouns that are not naturally divided into units (for example, English speakers say "three splotches of mud" because mud is a mass noun and *"three muds" is ungrammatical); count-classifiers, on the other hand, are not inherently "necessary" and thus only exist in a small set of languages
Edited sentence: Mass-classifiers are present in all languages since they are the only way to "count" mass nouns that are not naturally divided into units (as for example, "three splotches of mud" in English).On the other hand, count-classifiers are not inherently "necessary" and thus only exist in a small set of languages