First, here is a short video about language objectives. Please watch that so you have a brief introduction to language objectives. This article will go on to explain what language objectives are, why they're important, and how to incorporate them into your lessons.
Think back to your last year of college and your student teaching days. If your experience was anything like mine, you probably had to write many detailed lesson plans in which you detailed your objectives for the day. "Students will be able to..." Those are content objectives; they explain what the student is going to learn and how they will show it. Language objectives are similar, but focus on the language that students will need to acquire and use in order to meet those content goals.
The last few years, I feel like education in general has made a shift to the idea of every teacher being a language teacher, such as with the Common Core Standards requiring more writing in social studies classes. Language objectives can help in this because they inform all students about what language they will be expected to learn and use to show that they met the content objectives. They are especially helpful for English learners because although they might know the content, they may not have the language needed to show it.
Language objectives use all four domains (listening, speaking, reading, writing), vocabulary, language functions (justify, hypothesize), and language learning strategies (questioning, making predictions). I could try to explain this all day, but examples will probably be the most helpful.
I know we all have a lot to do and a lot to think about in every lesson. In a perfect world, every teacher would post content and language objectives for each lesson, but I think most of us would agree that that's not a reasonable expectation. Instead, simply start to consider what language students must know in order to meet the content goals for the lesson, and think about what you can do to scaffold those language requirements for EL students. You could provide examples of the language needed or sentence frames; give a quick lesson about how to write a summary; simplify text they must read; include number problems along with math story problems; or provide a list of vocabulary words and definitions.
If you do want to start writing language objectives for some lessons, here are some steps:
Here are some verbs you can use in language objectives:
Listening: tell, role play, identify, listen, recognize, point, show, follow directions
Speaking: name, discuss, rephrase, ask, answer, predict, say steps in a process, pronounce, repeat, respond, state, summarize, explain, tell, use
Reading: preview, read aloud, find specific information, identify, skim, explore, collect, distinguish, locate
Writing: list, summarize, ask and answer questions, create sentences, state and justify opinions, write, contrast, classify, record, categorize, match, draw
Vocabulary: define isolated words, define words in context, find words and construct meaning, use in a sentence
tl;dr Think about what language students need in order to meet your content goals for a lesson, and provide support to students who struggle with the language aspect of the lesson.
Here is an excellent site that explains language objectives!