The particle も is used to express inclusion, translating to 'too' or 'also' in positive sentences, and 'either' or 'neither' in negative ones. This versatility is a key feature of Japanese particles, which often serve multiple functions where English would require separate words to convey the same meaning in different contexts.

• 田中(たなか)さんは、学生(がくせい)です。
  Mr. Tanaka is a student.
• 私(わたし)も学生(がくせい)です。
  I am also a student.

Notice how English uses different words for agreement ('too' for positive, 'either' for negative), whereas Japanese uses も in both situations. The core function of も is to indicate that a statement that applies to one thing applies to another thing as well.

も frequently combines with other particles to create compound grammatical expressions like でも, にも～ない, or とも. In these forms, も generally maintains its core 'also' meaning, while contributing to a slightly different overall nuance.

• このケーキはおいしい、でも高(たか)い。
  This cake is delicious, and also expensive.

In this example, も joins with で to form でも. This structure implies that one quality is true, 'and in addition' another is true as well. Although frequently translated as 'but', the nuance is more aligned with 'and also'.