Easily the most expansive resource on this list, this website has it all, from guided videos to individual lesson plans. It encompasses vocabulary, grammar, and more, offering a solid group of resources to any first-time Hmong language learner: https://studyhmong.com/
A part of a longer project centered on the Southeast Asian diaspora, this website offers a free PDF download of a unique activity. A set of flashcards containing commonly used words, each page (and there are many) allows the reader to practice their tones in sequence! A great way to improve speaking skills and pronunciation even when alone, this resource has the added benefit of passively increasingly elementary vocabulary: https://www.theseadproject.org/projects_library/hmong-tone-flashcards-will-johnston/
Intermediate and Advanced Resources
One of the largest and most active Hmong-language forums on the internet, this website represents a compelling resource for intermediate and advanced speakers looking to improve their reading and writing comprehension in a real-world setting. Used by Hmong speakers throughout the diaspora, this website offers a unique opportunity to learn about the cultural context of the global Hmong community even as you work on your fluency. Be aware, however, that the boards, while separated by topic, are almost always a place for serious discussion within the community and should be respected as such: http://www.pebhmong.com/forum/.
The Dab Neeg Hmoob YouTube Channel is a fantastic resource for high intermediate and advanced speakers looking for an extended opportunity to listen to the language. The narrator speakers clearly with relatively little regional accent, making it easy to understand for the majority of Hmong language learners. Additionally, his use of simple language drives the plot along, anchoring the more expressive flourishes that represent some of the harder-to-learn aspects of the Hmong language. Overall, it is an excellent opportunity for those seeking to maintain their level of comprehension while adding expressive vocabulary to their repertoire: https://www.youtube.com/channel/UCdc21JPq8tynswDNSIbXRAg.
General Reference Sources
Google translate, for as accessible and expansive as it is, does not translate the Hmong language with any sort of accuracy. This resource, although limited to words and phrases, does an admirable job of filling the gap created by unhelpful online dictionaries. While you’re able to look up a small number of words each day before running into a paywall, this online dictionary is still one of the most reliable and accurate services around: http://www.hmongdictionary.com/.
Compiled through the University of Iowa’s Center for Language and Culture Learning, this website offers a compilation of many of the most well-respected Hmong language sources around. Most notably, this website includes links to RPA writing system primers, vocabulary lists, and syntax cheat sheets. In the end, this comprehensive resource acts as a mini-library, with something for everyone regardless of level or interest: https://lmc.uiowa.edu/resources/hmong-language-and-culture-resources.