A sound change is a change in the pronunciation of a word or language over time. In this case, the /t/ sound in 'water' has changed to a /d/ sound.

A grammatical change is a change in the way words are used in a language. In this case, the pronoun 'I' has changed to the object pronoun 'me' in the phrase 'I love you'.

A lexical change is a change in the vocabulary of a language. In this case, the word 'car' has been replaced by the word 'automobile' in the sentence 'I bought a new car'.

Assimilation is a common sound change in which one sound becomes more like a neighboring sound. For example, the /t/ sound in 'water' has changed to a /d/ sound because it is next to the /r/ sound.

The loss of case marking is a common grammatical change in which words no longer change their form to indicate their grammatical function. For example, in English, the word 'book' does not change its form to indicate whether it is the subject or the object of a sentence.

The borrowing of words from other languages is a common lexical change. For example, the English word 'computer' is borrowed from the Latin word 'computare', which means 'to calculate'.

All of the above factors can influence language change. Contact with other languages can lead to the borrowing of words and grammatical structures. Social and cultural changes can lead to changes in the way words are used. Technological changes can lead to the creation of new words and changes in the meaning of existing words.

All of the above changes have occurred in English over time. The case system, which was used to indicate the grammatical function of words, has been lost. The definite and indefinite articles, 'the' and 'a/an', have developed. And the word order has changed from subject-verb-object to object-verb-subject.

All of the above changes are currently happening in English. The use of 'like' as a discourse marker, the use of 'y'all' as a second-person plural pronoun, and the use of 'selfie' to refer to a photograph taken of oneself are all examples of language change.

All of the above changes are likely to happen in the future. The use of gender-neutral pronouns, the use of emojis in formal writing, and the use of voice commands to control devices are all examples of language change that is likely to occur in the future.

Comparative linguistics, historical linguistics, and diachronic linguistics are all terms for the study of cross-linguistic patterns in language change.

The neogrammarian theory, the generative theory, and the functionalist theory are all major theories of language change.

The neogrammarian theory of language change states that sound changes are regular and exceptionless. This means that a sound change will apply to all words in a language that contain the sound that is changing.

The generative theory of language change states that language change is driven by changes in the grammar of a language. This means that changes in the way words are used and combined can lead to changes in the sound system and the lexicon of a language.

The functionalist theory of language change states that language change is driven by changes in the function of language. This means that changes in the way language is used to communicate can lead to changes in the grammar, the lexicon, and the sound system of a language.