IT'S PROBABLY NOT NEWS to the tens of thousands of Hispanic Americans living in this community, but many others who expect to be around town this weekend should note that it's time once again for one of the most enjoyable and informative events held here each summer - the Hispanic American Festival. Though it is best known and attended as a family fiesta of music, food and dance, the festival is also an important opportunity for the "Anglo" society to learn about the frustration and concerns of local Latino people the year around.

Throughout this week, organizers of the festival have been conducting special programs to explain and honor the whole range of Hispanic American culture and its relationship to Greater Washington. Not only are they eager to share their rich and varied culture with everyone, but they seek to generate a deeper understanding of special problems that confront them quite aside from - or because of - language barriers: the complexities of cultural assimilation, immigration, citizenship, housing, planned parenthood, jobs, voting registration, teen-agers and the elderly.

This shouldn't be taken to mean that the festival is some sort of dreary indoctrination course. On the contrary, it is a joyful celebration that enlivens this city's international heartland of Adams-Morgan and Mount Pleasant, highlighted this weekend by family activities for all in Kalorama Park, capped by a grand parade at 1 p.m. Sunday with colorful floats, elaborately costumed dancers and, if our visits over the years are any indication, a grand variety of splendid foods. We know that the growing Latin population here looks to this celebration as a chance to share its life with others - and we hope that favor is returned by a large and warm attendence.