2Kids 学拼音- Written by 2kids.cn, the same company who wrote 2kids学汉字, this app aims to help your child learn and practice the sounds that make up Chinese (also known as Hanyu Pinyin). This app is written for children who already are familiar with the language and need to learn the writing system. However, this app is a good way for non-native speakers to practice Hanyu Pinyin after an introduction from another source.
This app is engaging for kids ages 3-7. It uses the same "Dora" type set-up that its counterpart uses. Children complete mini-missions by using what they've learned about Hanyu Pinyin.
The first set of lessons are free as an introduction to the app. There are two further in-app purchases that each cost about $3. I would recommend these purchases only if the child has someone else to help them learn the sounds. This app is inadequate by itself to teach Hanyu Pinyin.