A listening center can help students with their phonics. Oftentimes, second-language learners mispronounce words because they don't know how the English letters and sounds correspond with each other. They will use the sounds from their first language as a substitute. In order for second-language learners to learn the sounds, they have to hear them over and over again. Have your students listen to rhyming poems, rhyme word lists, poems with the same consonant at the beginning of words used frequently in stanzas, sounds when playing phonics bingo and word pairs that sound look and sound alike (men/man).
Syntax is the ordering of words in a sentence. One example of language interference due to syntax is a Spanish speaker saying "house white" for "white house." They say it that way because in Spanish "white house" is "casa blanca," literally, "house white." One listening center activity is to have pairs of students unscrambling sentences written on paper strips so that they read the words as they cut them out and put them together in the correct order. Another listening center activity can be done on a computer. Students can listen to stories on websites that automatically read to them. For example, some websites offer stories that are read to students as the words are highlighted on the screen.
Grammar is perhaps the most challenging thing to learn. Listening to stories being read using a website is one way to reinforce correct grammar. To search for these websites, use the keywords "free read aloud stories." Teach grammar by having students listen to such things. A list of correctly conjugated verbs doesn't really help students learn it; they need to have context (images and gestures) for the words they are learning so that they can understand what is being read. Grammar is best learned through natural language.
Listening centers can be organized to help students learn how to spell. First show them an illustration or gesture to help them figure out what the word means. You can videotape yourself using a computer saying and spelling words of pictures that you hold up to the screen. Students then go to the listening center and listen to the video.