A small set of high-frequency Spanish verbs deviate from regular patterns and must be memorized individually. The copula ser (to be, expressing identity) conjugates as soy, eres, es, somos, sois, son. Its counterpart estar (to be, expressing state) follows a different pattern: estoy, estás, está, estamos, estáis, están. Other essentials include ir (to go): voy, vas, va, vamos, vais, van; and haber (auxiliary 'to have'): he, has, ha, hemos, habéis, han, with the impersonal hay used for 'there is' and 'there are'.
The verbs tener (to have), hacer (to do/make), poder (can/be able), decir (to say), and venir (to come) all share a similar pattern of stem modification in the yo form: tengo, tienes, tiene, tenemos, tenéis, tienen; hago, haces, hace, hacemos, hacéis, hacen; puedo, puedes, puede, podemos, podéis, pueden; digo, dices, dice, decimos, decís, dicen; and vengo, vienes, viene, venimos, venís, vienen. Each introduces a unique yo form while keeping the third-person endings more regular.
Several other crucial irregulars round out the basic toolkit. Querer (to want/love) gives quiero, quieres, quiere, queremos, queréis, quieren. Dar (to give) conjugates as doy, das, da, damos, dais, dan. Ver (to see) becomes veo, ves, ve, vemos, veis, ven. Poner (to put): pongo, pones, pone, ponemos, ponéis, ponen. Saber (to know facts): sé, sabes, sabe, sabemos, sabéis, saben. Conocer (to know people): conozco, conoces, conoce, conocemos, conocéis, conocen. Traer (to bring): traigo, traes, trae, traemos, traéis, traen. Salir (to leave): salgo, sales, sale, salimos, salís, salen. Oír (to hear): oigo, oyes, oye, oímos, oís, oyen. These verbs form the backbone of spoken Spanish and appear constantly in everyday conversation.