To support ELLs in accessing math content and language, teachers will need to do quite a bit of language clarification. Some of this will entail the rewriting of questions from passive voice (ex. 16 subtracted from 32 equals 16) to active voice (32 minus 16 equals 16). Other situations will entail words with multiple meanings such as GROSS. In conversation it means disgusting, but in math, it means total income from sales.
If ELLs try dictionary definitions, they will be lost. Instead, this paper from NYU School of Education addresses how to make the language of math problems accessible through a variety of ways. First, wall charts that have vivid easy to follow definitions to assist students in determining the correct usage. Then there are graphic organizers such as venn-diagrams where, math "pictures" with their labels could be laid out in such a way as to show ELLs differences and similarities (difference: rhombus, square, rectangle---similarity: all 3 have 4 sides). Of course, there is also the need to highlight key vocabulary students need to know to be able to figure out what is being asked of them. With a document camera or an iPad, this can be done with ease. To build this skill, have paper handouts with word problems on them, have them highlight must-know words (with ERASABLE HIGHLIGHTERS), and then discuss meanings. If they highlighted the wrong words, they can erase them--no waste of paper for you and no loss of confidence for them. One of the strongest ways to support them is to have them keep math journals (inexpensive composition books will do here). They will note everything they learn there as well as problems they encountered and then solved. With a record to refer to in doing future problems, they are not starting from ground zero.
There are many more ideas here along with additional website resources (majority are free, but not all). Save the PDF in your DropBox folder and refer to it as needed. Think of it as a free e-book on math:)
ELL TEACHER PROS
OfficeMax Pen Style Chisel Tip Erasable Highlighters, 5 Colored
Composition Book, 7 1/2" x 9 3/4", Wde Ruled