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QUICK ANSWER
"El artículo" is a form of "artículo", a noun which is often translated as "article". "Lengua" is a noun which is often translated as "tongue". Learn more about the difference between "lengua" and "el artículo" below.
la lengua(
lehng
-
gwah
)A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
3. (education)
a. language arts  (United States)
Regionalism used in the United States
¿Han leído algo interesante en lengua este año?Have you read anything interesting in language arts this year?
b. Spanish  (in Spanish-speaking countries)
Soy negado para mates y eso. Me gustan mucho más lengua e historia.I'm useless at math and all that. I like Spanish and history a lot more.
el artículo(
ahr
-
tee
-
koo
-
loh
)A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
a. article 
En el diario de hoy, hay un artículo interesante sobre el cuidado de la salud.There's an interesting article in today's newspaper about health care.
b. entry  (dictionary)
No hay un artículo para esa palabra en el diccionario de la RAE.There's no entry for that word in the RAE dictionary.
2. (commerce)
a. item 
Aunque la fila para la caja de 15 artículos o menos se ve más larga, avanza rápido.Although the line for 15 items or less looks longer, it moves quickly.
b. article 
En esta tienda vendemos vajillas, utensilios de cocina y artículos para el hogar.This store sells tableware, kitchenware, and household articles.