I am entering into my second semester teaching high school English conversation to students, who I would characterize as low level mostly.  I would say that they range from low beginner to high beginner level.  I'm sure this situation is similar for many of you:  Most students have learned in the past and know a lot of  vocabulary words, and can respond with with one or two words if prompted to do so,  but very few can put a sentence together.  Therefore, I've decided that teaching them this skill is my primary goal this semester.

What kinds of lessons, activities, games etc. work well for teaching sentence structure and moving students beyond the ability to only produce short utterances?  What has worked for you in the past?  Do you think listen and repeat is a good method to use with these kids?  What else is effective?  One thing I've been experimenting with is cutting up sentences and having them rearrange them and making it into a game.  I also did an activity last semester  where they had to find the other half of the sentence.  Other ideas?  Also, if you have any great games for this, I would be most grateful if you would post them here.  Please share your ideas.  Thanks!

Here's a sentence cut-up lesson I use.  The students must complete the sentences which make up the steps of a magic trick.  Works fine using just paper, but I print the pages, cut the sentence chunks I want to use (usually prepositional phrases, articles with nouns attached,etc.), number the backs of each chunk with a corresponding sentence number to keep them organized and finally place them spaced apart on some coating material to laminate them.  After that, when you cut them out and let the kids use them, they are more durable and can be used again in the future.
Kids get motivated to learn the trick and I feel it helps them at least start to nail down the subject+verb+object sentence structure a little better. Hope this helps.

Unfortunately, you have to teach the boring part first.  Kids need to learn what makes up a sentence and need to be able to distinguish between sentences and phrases (incomplete sentences) before they can really be expected to form sentences of their own. 

I would start with phrases because they're so easy to teach.  Students commonly start sentences with conjunctions because that's what we do when we speak - we're more likely to speak in phrases than sentences.   Try making a list of phrases with one or two full sentences (simple sentences) mixed in and aske the kids to identify the phrases.  Make the mistakes in the phrases very obvious - missing subject, missing verb, missing objects - and ask the kids if they can correct the error.  You could turn it into a game: 2 - 4 teams, the first team to identify it as a phrase/sentence gets a point; if that team can also turn the phrase into a full sentence, they get 2 bonus points, if not, it's opened to other teams to try and they get 1 point. 

Once you've got them to distinguish between phrases and sentences, start giving them jumbled simple sentences with a picture relating to the sentence.  Ask them to unscramble the words to form a sentence that explains something in the picture.  To scramble them initially, just move one word (like the verb to the end) to a different place in the sentence then move up to scrambling the word order entirely. I would keep the sentences to 8 words or less.  You then start giving them compound sentences - again keep the two simple sentences short - with the same activity and slowly build up their sentence length.

When they're comfortable with unscrambling sentences, give them just the pictures (from the PPTs you've been using thus far) and have them form the sentences themselves.  For some, they'll be able to simply recall the sentences they've unscrambled but there'll still be enough independent thinking required in the actual sentence formation.  If they manage this successfully, give them different pictures that allow them to use the same vocabulary they've been using (you could also start with new vocabulary with no more than 5 new words at the begin of each lesson) and have them form their own sentences similar to the ones you've given them in previous lessons. 

When they're able to do all of these activities successfully, I would move away from PPTs and have them form short sentences using two words provided by you.  You could make dice (www.mes-english.com - there's a dice maker somewhere on there) with words on each side.  Have them throw the dice and use that word in a sentence of their own.  You can also use questions that the students have to practise asking and answering in pairs - keep alternating who asks and who answers the questions.  Then have the come up with a list of 5 questions of their own. 

The possibilities are endless.  If you need more ideas, give me a shout.  Hope this helps!

A slight variation on the cut up thing- you could make the students themselves be the different parts of a sentence- print the various bits out on A4, and give one to each student.  Put them in teams, so that they have a certain amount of time to put themselves in the correct order- thus it becomes a game and something that kinaesthetic learners will enjoy...

One thing that has worked pretty good for me has been "Disappearing Dialogue." Basically, I just make a powerpoint, write a dialogue of 4-5 sentences (using grammar and sentence structure of lesson), and have students repeat it. Then, the next slide, I take away some of the words (put blank spaces instead) and so on and so forth until they are repeating the whole dialogue from memory.

It is still basically a bunch of repeating, but students seem to like the challenge (or maybe just the reward youtube video I always give them if they succeed!). Best of all, it's fairly easy to do, and it definitely seems to help them with sentence structure.

This is great! My students are extremely low level and so having to create the sentences themselves gave them sentence stucture practice. My girls really enjoyed it.