Error catalogue
Common Spanish mistakes and how to fix them
YabLab classifies every slip in your writing against a closed taxonomy of learner errors — grounded in the annotation of the COWS-L2H and CEDEL2 learner corpora. Each entry below is a real, drillable rule: the checker spots it, explains it in your language, and helps you practice it until it is gone for good.
Grammar topics explained
- Ser vs estar: when to use each in Spanish
- Preterite vs imperfect: when to use each in Spanish
- Por vs para: how to choose in Spanish
- Spanish subjunctive: when to use it
- Spanish direct object pronouns (lo, la, los, las)
- Spanish accent marks: when to write them
- Saber vs conocer: which “to know” to use
- Stem-changing verbs in Spanish (e→ie, o→ue, e→i)
- Irregular preterite verbs in Spanish
Spelling & word form 18
- Spanish accent marks: missing tilde
- Spanish accent marks: tilde where none is needed
- Accents that change meaning: él/el, tú/tu, sí/si
- Accents on question words: qué, cómo, dónde
- Accent marks in plurals: examen → exámenes
- Spelling: b versus v
- Spelling: c, s or z
- Spelling: g versus j
- Spelling: silent h
- Spelling: ll versus y
- haber versus a ver
- hay, ahí or ay
- porque, por qué or porqué
- sino versus si no
- Word boundary: wrongly joined
- Word boundary: wrongly split
- Lowercase: nationalities, months, days
- Capitalization: sentence start
Grammar 64
- Gender: wrong article
- Gender: el agua, el águila
- Gender: exceptions to the -o/-a rule
- Plural: wrong form
- Plural: unchanged nouns
- Agreement: noun and adjective
- Agreement: determiner and noun
- Agreement: predicate adjective
- Subject–verb agreement
- Agreement with a distant subject
- Ser vs estar: ser used for a state
- Ser vs estar: estar used for identity
- Ser vs estar: place vs event
- Ser vs estar: when the verb changes the meaning
- Stem-changing verbs in Spanish: e→ie, o→ue
- Irregular yo forms in Spanish: sé, tengo, hago
- Irregular preterite in Spanish: wrong stem
- Irregular Spanish verbs conjugated as regular
- Wrong person ending
- Preterite vs imperfect: preterite for the background
- Preterite vs imperfect: imperfect for a single event
- Present perfect versus preterite
- Compound past: haber as auxiliary
- Conditional form
- Future: ir a versus simple future
- Pluperfect for an earlier past
- Spanish subjunctive after querer que and requests
- Spanish subjunctive after emotions (me alegro de que)
- Spanish subjunctive after doubt: no creo que
- Spanish subjunctive after cuando and para que
- Spanish subjunctive in relative clauses
- Subjunctive vs indicative: creo que + indicative
- Imperfect subjunctive: si tuviera, not si tendría
- Conditional sentence: tense pairing
- Tense shift in the subordinate clause
- Affirmative tú imperative
- Negative imperative takes subjunctive
- usted imperative
- Spanish direct object pronouns: lo, la, los, las
- Spanish indirect object pronouns: le, les
- Leísmo: le instead of lo or la
- Double object pronouns: se lo, not le lo
- Doubled pronoun in Spanish: a mí me gusta
- Reflexive pronoun: wrong person
- Missing reflexive pronoun
- Impersonal se: verb agreement
- se for accidental events
- Irregular past participle
- Participle stays unchanged after haber
- Article with generic nouns
- Article: missing
- Article: redundant
- Body parts take the article, not a possessive
- Possessive agreement
- Ambiguous su — say de él, de ella
- Spanish requires the double negative
- Choice of negative word (nada, nadie, ningún)
- Irregular comparative (mejor, peor, mayor)
- Comparative structure (más que, más de)
- Superlative form
- Infinitive as subject, not gerund
- Gerund cannot modify a noun
- Verb periphrasis needs its preposition
- al + infinitive for "when…"
Word grammar & complementation 14
- Preposition: a versus en
- Preposition: de
- Preposition missing or redundant
- Por vs para: para for purpose
- Por vs para: por for cause and exchange
- Por vs para: para for deadlines
- Verb governs a fixed preposition
- Adjective governs a fixed preposition
- Personal a before a human object
- Personal a not needed here
- gustar agrees with what is liked
- gustar: the person is an indirect object
- Missing obligatory object
- Redundant object or complement