The definite articles: el, la, los, las
Spanish has four definite articles depending on gender and number: el for masculine singular (el gato), la for feminine singular (la casa), los for masculine plural (los gatos), and las for feminine plural (las casas).
Present tense of -AR verbs
Most Spanish verbs end in -ar in the infinitive (hablar, cantar, amar). Drop -ar and add: -o, -as, -a, -amos, -áis, -an. Example: hablar → yo hablo, tú hablas, él/ella habla, nosotros hablamos, vosotros habláis, ellos/ellas hablan.
Adjective agreement
Spanish adjectives agree in gender and number with the noun they describe. Most add -a for the feminine (alto → alta) and -s for the plural (alto → altos). Adjectives ending in -e or a consonant often stay the same in the feminine (verde → verde, feliz → feliz).
Negation with no
Spanish negates a verb simply by placing no directly before it: no sé (I don't know), no quiero (I don't want). Unlike French, there's no second negative word required in a simple negative sentence.
Forming plural nouns
Nouns ending in a vowel add -s to form the plural (un gato → dos gatos). Nouns ending in a consonant add -es (una ciudad → dos ciudades). Nouns already ending in an unstressed -s with more than one syllable don't change (el lunes → los lunes).
Possessive adjectives: mi, tu, su
Short-form possessives agree in number (not gender, except nuestro/vuestro) with the thing owned: mi/mis (my), tu/tus (your, informal), su/sus (his/her/your formal/their). Example: mi hermano (my brother), mis hermanos (my brothers).
Present tense of -ER and -IR verbs
-ER verbs (comer, beber) conjugate: -o, -es, -e, -emos, -éis, -en. -IR verbs (vivir, escribir) conjugate: -o, -es, -e, -imos, -ís, -en. Example: comer → como, comes, come, comemos, coméis, comen; vivir → vivo, vives, vive, vivimos, vivís, viven.
Ser vs. estar (two verbs for "to be")
Spanish splits "to be" into two verbs. Ser is for lasting, defining characteristics — identity, origin, profession, permanent traits (soy de España, es médico). Estar is for temporary states, locations, and conditions (estoy cansado, el café está caliente). The same adjective can shift meaning depending on which verb is used: es aburrido (he's boring) vs. está aburrido (he's bored).