For phonograms (Orton Gillingham type) use Phonics with Phonograms by Logic of English
https://itunes.apple.com/us/app/phonics-phonograms-by-logic/id604337610?mt=8
For vocabulary, try some apps focused on delivering audio books, such as:
Audible
https://itunes.apple.com/us/app/audible-audio-books-original/id379693831?mt=8
OverDrive (great if your local library has books for this)
https://itunes.apple.com/us/app/overdrive-library-ebooks-audiobooks/id366869252?mt=8
Or, just subscribe to podcasts directly in iTunes (or any other podcast player):
Family Folk Tales
https://itunes.apple.com/us/podcast/family-folk-tales/id292366477?mt=2
Sparkle Stories Podcast
https://itunes.apple.com/us/podcast/sparkle-stories-podcast/id680194129?mt=2
Barefoot Books Podcast
https://itunes.apple.com/us/podcast/barefoot-books-podcast-ipod/id361242548?mt=2
The Story Home Children's Audio Stories
https://itunes.apple.com/us/podcast/story-home-childrens-audio/id270352658?mt=2
Storynory - Stories for Kids
https://itunes.apple.com/us/podcast/storynory-stories-for-kids/id94571049?mt=2
Finally, I've found that the YouTube Kids app builds vocabulary because it supports voice search. This helps kids find videos about stuff on their own that they're really interested, even before they can read or spell fluently.
https://itunes.apple.com/us/app/youtube-kids/id936971630?mt=8
Enjoy!
Sally, Founder, Story Hour Academy
https://storyhouracademy.com