ASL is not English
American Sign Language is its own language, which means it has its own vocabulary and grammar. The grammar -- including how words and sentences are formed -- is different from English. It's best to practice this early on, so you don't default or become too attached to signing in English word order.
As with other languages, there isn't necessarily a *single* correct way to express a thought. With that in mind, here are a few general rules and patterns to understand, look for, and practice.
basic sentences: Topic-Comment
The generally accepted and used sentence structure in ASL is referred to as "Topic-Comment" structure. This means that the central information -- the thing you're about to talk about -- goes first in the sentence. Once you've identified the topic, then you make a comment or ask a question.
The topic may or may not be the subject of the sentence. So sometimes the word order aligns with English (in subject - verb - object syntax), and sometimes the word order is different from English (it might use object - subject - verb syntax).
English: "I'm excited." ASL: ME EXCITED. (Remember from the Starter signs that "ME" can also translate as "I am".)
English: "I like cookies." ASL: COOKIES, I LIKE. (Notice how we put the topic of the sentence first, and then commented about it.)
English: "My sister gave me her book." MY SISTER, HER BOOK, SHE-GIVE-ME. (Now we first identify our sister, then mention the secondary topic: her book. Finally, we explain that she gave it to me.)
This is also a good time to mention the sign GIVE, which includes the subject and object. So instead of signing separately SHE, GIVE, ME, the sign "GIVE" is made with one fluid movement from my sister to me. More on this next!
"yes or no" questions
For questions that expect an answer of yes, no, or maybe, the signs and word order remains the same as regular sentences. ASL does not add words like "Do..." or "Are..." or "Can..." to questions. Instead, simply sign the sentence as if it were a statement, but use your facial expression to change it to a question:
Raise the eyebrows (think: a "surprised" look)
Hold the last sign
For questions that require an answer beyond yes or no -- think who, what, where, when, why, how -- the facial expression changes. As a general rule, put the question word last in the sentence, and use the following facial expression:
Furrow (lower) your eyebrows (think: a "confused" look)
Hold the last sign (the question word)
Many verbs in ASL are what's called directional. These are transitive verbs, meaning there's an action performed and there is an object to the action. As a result, ASL makes use of space to indicate who is involved in the action.
For example, above we used the example GIVE. The verb "give" has a subject (the giver) and an object (the recipient). As a result, we don't need to separately sign "SHE" or "ME" or the names of people involved. The sign GIVE includes this information.
However, remember that we first establish the topic, so we already know who is "where" in space. "I" am me -- located physically where I am. Other people are either present where you're conversing, in which case you point directly to them to say
TIME and TENSE
In ASL, verbs are not modified based on tense. In other words, there's no difference between the past, present, and future versions of the word "go", for example. The English words "go", "went", "going", and "will go" would all generally translate the same way.
So how do we know what tense someone is using? In ASL, tense is established by stating the time/tense at the beginning of the sentence or story. Once a time is established (such as "Last night...", "Next month...", or "In 2012..."), the tense persists until a new tense is established.
The beginner course American Sign Language Made Simple introduces this concept, and an upcoming course will teach time and tense in more detail.