French verbs are divided into three groups depending on their ending in infinitive:
First group ends in -er, like parler=to talk/speak or manger=to eat. To this group belong all verbs ending in -er except aller=to go vhich is irregular.
Second group ends in -ir, like finir=to end, mourir=to die. To this group belong all regular verbs ending in -ir.
Third group ends in either -er (only aller), -ir (irregular -ir verbs) or -re, like lire=to read or faire=to do/make
Within a group is the conjugation pattern similar, while there is a greater difference between the groups or within the third group which contain all irregular verbs.
So, the answer to your question is that the two verbs you asked about have different conjugations patterns because they belong to different verb groups.
From what I gathered online it is optional to use a liaison after a verb (unless it's followed by a pronoun, in which case it is required) but people only do it in really formal speeches. Here's a source: http://french.about.com/library/pronunciation/bl-liaisons-o.htm Also, this is not the case but with the verb "être" it's usually seen as required to form the liaison, though it's classified as optional in this website I posted above.
Since French does not have an equivalent of the English Present Continuous tense, the French present tense may be translated as either EN "simple present" or EN "present continuous". This mean that "elle lit" may be "she reads" or "she is reading". When a French speaker wants to emphasize that an action is going on at this very moment, it would be "elle est en train de lire un journal". The "en train de" is generally not translated into English at all but it does emphasize that the action is occurring right now.
When you translate, you must understand the full meaning of the sentence before you translate it to another language, i.e., you must understand the French sentence in your mind before you translate it. This means that you really can't approach the task of translating by looking at one word at a time. As you see, there are words that have completely different, unrelated meanings. If you locked onto "lit" as "bed", what would that possibly mean: she bed one newspaper. You must realize this. The solution: if it doesn't make sense, it's not right. The sentence is a simple example of a subject + verb + object. Elle (she) lit (reads/is reading) un journal (a newspaper).
In English, you have "read", valid for I, you, we, they and "reads" valid for he, she and it.
In French, conjugations are much more extensive:
- je lis (I read), tu lis (singular you read), il/elle/on lit (he/she/it/one reads), nous lisons (we read), vous lisez (formal singular or plural you read), ils/elles lisent (they read).