Here’s another way I’ve used Google Voice to evaluate speaking.  I’ll briefly detail the four days from presentation of vocabulary to student retells.

We were using the unit, “un accidente de autobus”.  Vocabulary and text here.

Day 1: Presentation of vocabulary and personalized questions.

Day 2: In-class story.

Day 3: Class rewrite.  The class collectively retells the story while a volunteer student types.  The text is projected.  This step can be a bit dull, but it is important for students to see the story reconstructed.  It also helps me remember what happened in each class, so I can draw the pictures.

Day 4: Students are given a set of pictures from their story and instructions to call the Google Voice number and leave a message.  Their message is their summary of the story.  The pictures are used as a reference.  Students may expand as they need.