Hi Pat,

It’s worth bearing in mind that with a number of specific exceptions, verbs conjugated in the pretérito perfecto (e.g. has llamada) are translated as if they were in the pretérito indefinido. The “have” is dropped - and you will see this throughout the course.

In modern English usage we use the pretérito perfecto in all sorts of circumstances but with Spanish it is more precise. This quirk of translation is confusing for us English speakers but whenever you see this tense it is referring to the fact that the action took place in the "now" or current time period e.g. today (this day), this morning, this evening, this week, this month (common denominator “this”). These are regarded as "unfinished" periods of time. Therefore “Le diré a mi hijo que has llamada (pretérito perfecto)” must be referring to one of the periods given above. Invariably in speech more detail would be given for example "Le diré que has llamado esta mañana, - I will tell my son that you called this morning." 

The conjugation “llamaste” (pretérito indefinido) is translated the same way as above, but refers to the fact that the action happened in the past and is now completed. An example sentence in this case would be "Le diré a mi hijo que llamaste la semana pasada, y todavía esperas una respuesta - I will tell my son that you called last week and are still waiting for a reply." Last week, month, year etc are regarded as "completed" periods of time. 

Here is a great link from Kwiziq to explain this better. 

María José from AIL Madrid explains 'marcadores temporales con pretérito "indefinido" y "perfecto"'. (By the way, AIL is an excellent school and highly recommended if you want to learn Spanish in Madrid!)

Saludos. John