Andorra: The motto on the coat-of-arms stresses a Catholic corporatist culture with "Virtus Unita Fortior" meaning "United Virtue is Stronger."
Belize: "Sub Umbra Floreo" on the coat of arms translate to "Under the shade I flourish"
Dominican Republic: Besides its Spanish name, the flag's coat of arms stresses the values of God, Country (fatherland), and Liberty
Equatorial Guinea: This Spanish-speaking African republic's motto "Unidad, Paz y Justicia" means "Unity, Peace, and Justice."
Haiti: "L'Union Fait La Force" means "Unity Makes Strength." Haiti is not a strong country.
Malta: This former Knight-state prizes its past and British World War II medal honor phrase of "For Gallantry" which is on the George Cross
Spain: The Spanish prize their early explorations to the New World and push themselves towards the future with "Plus Ultra" meaning "Further Beyond."
Afghanistan: The modern flag of Afghanistan is the former monarchy flag with "Afghanistan" spelled at the bottom with the addition of the shahada, the Muslim profession of faith.
Iran: The white text in the green and red spells out Allah-u-Akbar meaning God is great
Iraq: The flag has Allah-u-Akbar on it as well. The text was once in Saddam's hand writing but changed to a general font to de-Baathify the flag.
Saudi Arabia: Also has the shahada
*Somaliland: The unrecognized but in control republic has the shahada
El Salvador: Citizens are never lost as the Spanish-language sentence says the Republic of El Salvador in Central America.
Nicaragua: Nicaragua also states it's existence in Central America
Guatemala: No one forgets that liberty was achieved on September 15, 1821 because that's what the Spanish-language document says on the flag.
After looking at about 200 independent countries and de facto countries, it is clear that words on flags are uncommon. Even more so when one throws out coats of arms. National, mostly secular, mottos are the most common. These try to unite the state and people in common values. Muslims have complete dominance on religious text on flags. Christian and post-Christian countries meanwhile have dominance over Muslims in the Cross versus Crescent flag battle. El Salvador and Nicaragua both base their flags closely on the former Federal Republic of Central America and have modified the text to keep the geolocation. Finally, Guatemala is the only country to spell out its independence day but others like Belize and Brazil use symbolism to represent the date.