Since ASL is a visual-gestural language, not a spoken consecutive language, it can only truly be recorded in video and not captured in writing. Many writing systems have been developed for ASL, but none of them have reached a critical mass; this is probably because it is difficult to capture handshape, location, palm orientation, movement and non manual signals in a written form. For that reason, when describing ASL word order, many people rely on the linguistic convention called "glossing", which means writing a word in your native language for each sign that appears. This is not a perfect system, but it can be useful when discussing the syntax of other languages, signed or spoken.
You can read more about interlinear glossing on Wikipedia.
When writing an English gloss for an ASL sentence, a few conventions are followed:
|Signs are capitalized||BOY, HOUSE, ME|
|If a sign requires more than one English word to communicate the idea of one ASL sign, you can use dashes in between the words to indicate is is one sign for two or more English words.||3-MONTHS, HOUSE-FOR-SALE, KNOW-NOTHING|
|Words that are fingerspelled have dashes written between the letters||M-A-R-Y, D-O-G, S-A-L-E|
|When a fingerspelled phrase has become lexicalized, that is, it starts to resemble a sign, you precede it with a #. You can read more about lexicalization here.||#SALE, #MICH, #FAV.|
|Depicting verbs (classifiers) are written as CL:||CL:3 (vehicle)
CL: 55 (feet)
CL: CC (telephone pole)
|When a sign is reduplicated, you add a + at the end||STUDY++, READ++, GOAL++|
|When a compound sign is formed by combining two signs according to ASL rules (see your linguistic textbook or a teacher for more information), you separate the signs with a ^||THINK^CONTACT++ (obsession)
|When one sign is emphasized, either with weak hand epenthesis (eg, a one handed sign like HELLO being signed with two hands) or with a elongated hold and quick movement (eg, the sign for HUNGRY which usually has a deliberate movement being signed once very quickly to mean "starving"), you add !||HOPE ! (expect)
BLUE ! (bold blue)
SILLY ! (ridiculous)
|When a part of a sentence is grammatically inflected, you draw a line over the signs that have the specific non-manual signal. Above the line, you can clarify which type of grammatical inflection.||
topicMY SISTER SHE LIKE EAT #PIZZA
conditionalIF TODAY RAIN WE CANCEL TOUR WILL
whYOUR NAME WHAT
ynYOU LIKE THAT RESTAURANT
When referring to the first person (me or I in English), you can write PRO1. PRO2 stands for second person (you in English) and PRO3 stands for third person (he, she, or it in English)
These are not all of the conventions, these are only a few. For more information, see your sign language textbook, or check a linguistics book.