This paper presents the selection of singular/plural forms of the impersonal verb haber, one of the most interesting phenomena of spoken and written Spanish nowadays. These forms, according to the standard/non-standard uses respectively based on the Spanish academic norm, have always been subject to debate among grammarians and linguists on both sides of the Atlantic. Therefore, the article considers beforehand several existing studies and examples of the verb haber throughout the evolution of Spanish. For the purpose of dealing with the subject in the field of education, we included traditional grammars in Spanish and the contents of grammar books dedicated to international and Korean students. In traditional studies, the meaning of ‘existence’ of the verb is highlighted and its plural use is sometimes added. Most resources for learning Spanish explain the impersonal form in present hay at the basic level without mentioning its singular form in other verb tenses. To know the influence of these explanations on Korean students who learn and speak Spanish, we have obtained related corpus with interviews consisting of 26 questions. Results from sociolinguistic analysis indicate that all survey participants knew the impersonal verb haber always remains singular in present tense, whether the noun phrase that follows is singular or plural. Nevertheless, it does not occur the same in the past and future verb tenses since 35% of the respondents pluralize this verb in simple tenses and 44% in compound tenses. Finally, we add a reflection on whether the pluralization of haber can be linked to Spanish-speaking countries where students learn the language or is it a mere confusion that they make in relation to its auxiliary function.