LINGVA LATINA
 
  There are five declensions for nouns in Latin language: they are  first, second, third, fourth and fifth declensions. Although, there are minority of nouns which do not fallow the same patters, or have some peculiarities, most of the nouns are regular. It might seem hard to learn them in one day, but writing nouns in Latin sentences will make learning process easier. Here are the declensions:
  First Declension
 Nouns of this declension usually end in -a. Most nouns are feminine in first  declension with a few exceptions. Such as, m.nouta (sailor), m.agricola (farmer), m.scrība (clerk). Genitive case of this group's nouns end in -ae. There are some nouns from Greek, and their endings might differ. Consequently, they can be declined differently.
 Please click and see how nouns are decline in table 1 and 2.
 Second Declension
 It's a large group of nouns. Most of the nouns are masculine with some neuter, and feminine nouns in this group. Most of the masculine nouns end in -us, -er and -r. Neuters end in -um. They have their genitive case in . Once again, some nouns were borrowed from Greek and are inflected with a varying mixture of Greek and Latin endings .
 
Please click and see how nouns are decline in table 3 and 4.
 Third Declension
 It is the largest group of nouns with various endings. When a new word was absorbed into Latin, it was added to this group. This is probably the reason for  nouns with various endings in this group. Their endings can be in: -a, -e, -i, -o, -y, -c, -d, -l, -n, -r, -s, -t, -x. There are masculine, feminine, and neuter nouns with various nominative endings. Without certainty, some masculine, feminine and neuter nouns' endings can be given:  neuter: -a, -e, -i, -y, -l and -t, masculine ( sometimes of other genders' endings): -o, -or, -os, -eus, feminine (sometimes masculine): -as, - aus, -es, -is, -ys, -bs, -ns and -ps. This groups'   genitive ending is -is.
Please click and see how nouns are decline in table 5 and 6.
 Fourth Declension
 Most of the nouns are masculine except some feminine nouns, such as: manus (hand), donus (house), and neuter nouns like genū (knee). Masculine and feminine nouns end in -us and neuter ones end in . Their genitive ending is -ūs.
Please click and see how nouns are decline in table 8.
 Fifth Declension
 It is a small group of nouns which are mostly feminine except diēs (day) (note: diēs can be masculine on notable days). Their genitive ending is i -ei, and nominative ending is in -es.
Please click and see how nouns are decline in table 9.
 
  Latin is an inflected language. Unlike English, words change according to their functions in Latin. Though, some words change in English as well.
For instance:
       I see you, but you can't see me.
  In this sentence, "I" is replaced by "me". (objective pronoun)

  In Latin, nouns, pronouns, and adjectives change according to their functions in a sentence. In this process, endings of nouns change with a number of regular patterns. These patterns are called declensions. There are 5 declensions of Latin nouns which I will mention later.  Now, we will take a look at cases in order to learn how they function in a sentence.  There are 7 cases which are nominative, vocative, accusative, genitive, dative, ablative and locative. (note: 'locative case' is rarely used.) 6 cases are used frequently.
 Another important point to mention is that case of a word also varies according to its gender (masculine, feminine, and neuter), singularity, and plurality of it.
I will demonstrate only how cases operate in a sentence. So, don't worry if you don't figure out everything.

1. Nominative Case

  It is the case of subject in a sentence. (note: highlighted word is in nominative case)
    Marcus laborat.
    Mark works.

2. Vocative Case
 It is the case which is used to address or call someone or something.
    o fortuna!
    Oh fortune!

3. Accusative Case
 
It is the case of object in a sentence.
     Quintus Marcum salūtat.
     Quintus salutes Mark.

4. Genitive Case

 It is used, as 'of' in a sentence, or  to show possession.
    bellī deī.
  
War of gods.

5. Dative Case
 It is used, as 'to' and 'for'.
    lactem felibus do.
    I give milk to the cats.
 
6. Ablative Case 
 
It is used, as 'by', 'with', 'from', 'at', 'in', or 'on' in a sentence. Ablative case operates like a proposition. However, it can be used with a preposition as well. In classical Latin, usage of propositions with ablative case is less frequent than in Vulgar or, Medieval Latin. Moreover this gives us more clues about evolution of Latin through oromance languages. I will give examples in advanced posts.
    Marcus vīnum forō emit.
    Mark buys vine from the forum.

7. Locative Case
 It is used to indicate the place where something is happening:
    Rōmae
    At Rome