I have a 5 year old who has mild speech apraxia. One thing I can say from meeting other parents of kids with apraxia is the importance of finding an SLP who has specific training in apraxia therapy. Apraxia therapy is different than regular speech therapy techniques and there are many SLPs that don't do apraxia therapy. One woman I know spent years in regular speech therapy with her son who has apraxia and saw very little improvement. Once she moved to an SLP w/ an apraxia specialty, she saw incredible progress. Thankfully after years of great therapy, my DS is doing really well and is almost completely up to speed with his peers verbally. A great website for resources is CASANA:
http://www.apraxia-kids.org. Good luck!