Pronoun - It substitute nouns to avoid redundancy.
Adjective - Modifier, it modifies nouns and pronouns.
Verb - State of being, action or state words.
Adverbs - Modifier, describes a verb, adjective, or another adverb.
Preposition - It denotes time, place, and direction.
Conjunction - connecting words.
Interjection - It denotes a strong feelings or expressions.
Shortened Words - These are shortened version of words which are also being generally accepted in modern english. (ex. refrigerator to ref)
Acronyms - These are being made up by taking the first letters of words building up a name. They are also sometimes pronounced as actual words themselves. (ex. LOA, STEM, ABM, HUMSS, ICT)
Punctuation - These are standardized abbreviations which end with a period to indicate a full stop and express that a word is indeed an abbreviation of something. (ex. kg, nov., mr.)
Abbreviation in Writing - These are abbreviations that are standard in all forms of academic writing. (ex. et al., i.e., e.g., ed.)
Period - (.) To end sentences, to abbreviate, for decimals.
Comma - (,) To separate clauses, to separate items in a list, for addresses.
Colon - (:) To introduce items in an enumerated list, for titles, for ratios, for letter salutations.
Semi-Colon - (;) To separate clauses, to separate long items in a list.
Parentheses - ( () ) To enclose additional information about certain subjects.
Quotation Marks - (" ") To enclose direct speeches (exact statements).
Exclamation Point - (!) To end exclamatory sentences, seldom used in technical writing.
Question Mark - (?) To end interrogative sentences.
Ellipses - (...) Put at the end of incomplete sentences.
En dash - (-) Used in replacement of "to" or to show distance between place and time, as well as to hyphenate compound words.
Em dash - (–) is used to immediately cut off sentences.
Slash - (/) For dates, for fractions, in replacement of "per".