Null subject language

A null subject language, in linguistic typology, is a language whose grammar permits the omission of an explicit subject. This phenomenon is similar, but not identical, to that of pro-drop languages, which may omit pronouns, including subject pronouns.

In null subject languages, the grammatical person of the subject is generally reflected by the inflection of the verb. This is not always the case; for example, Chinese and Japanese verbs do not inflect for person.

In certain null subject languages, though an explicit subject is not strictly necessary to form a grammatically correct sentence, one may be stated in order to emphasize its importance.

Many Asian languages that are null subject at the sentence level nevertheless require an expressed topic in order for sentences to make sense. In Japanese, for instance, it is possible to start a sentence with a topic marked by the particle wa, and in subsequent sentences the topic can be left understood, until another one is explicitly introduced. For example, in the second sentence below, the subject ("we") is not expressed again but left implicit:

Watashitachi wa kaimono o shimashita. Ato de gohan o tabemashita.
:Lit.: We (TOPIC) shopping (OBJ) did. After (COMPL) dinner (OBJ) ate."We went shopping. After that, we ate dinner."

Other languages (sometimes called non-null subject languages) require each sentence to include a subject — this is the case for most Germanic languages, such as English and German. Even in these languages it is sometimes possible to omit the subject, although contextual clues are usually necessary."Bumped into George this morning." (I)"Agreed to have a snifter to catch up on old times." (We)"Told me what the two of you had been up to." (He)"Went down to Brighton for the weekend?" (You)

Examples of null subject languages are Latin, most Romance languages (including Spanish, Italian, and Romanian), Arabic, Hebrew, Chinese, Japanese, and Tamil.

Examples

Null subject language:
: Spanish: Te quiero (object - conjugated verb) -- the ending of the verb "-o" indicates the first person

Non-null subject language:
: English: I love you (subject - verb - object)