Introduction
One of the most common mistakes that English-speaking learners make when studying Spanish is the incorrect placement of indirect and direct object pronouns. If you have ever written or said Se lo voy decir thinking it was correct, you are definitely not alone. This phrase represents a classic pronoun placement error that trips up countless Spanish students at the beginner and intermediate levels. Understanding why this construction is grammatically incorrect will help you master one of the most important aspects of Spanish grammar and communicate more naturally with native speakers. In this comprehensive guide, we will explore the rules governing Spanish pronoun placement, explain exactly what makes Se lo voy decir wrong, and show you the correct way to express this idea in Spanish.
Understanding Spanish Object Pronouns
What Are Direct and Indirect Object Pronouns?
Before we can understand why Se lo voy decir is incorrect, we need to establish a solid foundation in Spanish object pronouns. Spanish has two types of object pronouns: direct object pronouns and indirect object pronouns.
Direct object pronouns replace the person or thing that receives the action of the verb directly. In English, these are me, you, him, her, it, us, and them. In Spanish, the direct object pronouns are: me, te, lo, la, nos, os, los, and las.
Indirect object pronouns replace the person who receives the benefit or detriment of the action. These answer the question to whom? or for whom? In Spanish, the indirect object pronouns are: me, te, le, nos, os, and les.
Notice that some pronouns overlap between the two categories. This is important because when you use both a direct object pronoun and an indirect object pronoun together in the same sentence, they must follow specific ordering rules.
The Pronoun Ordering Rule: Indirect Before Direct
The fundamental rule for Spanish pronoun placement when using both pronouns together is straightforward: the indirect object pronoun always comes before the direct object pronoun. This is the exact opposite of what many English learners intuitively expect.
The basic pattern is: [Indirect Object Pronoun] + [Direct Object Pronoun] + Verb
For example, if you want to say I am going to tell it to him, the structure would be:
Indirect Object Pronoun: le (to him)
Direct Object Pronoun: lo (it)
Verb: voy a decir (I am going to tell)
This gives us the correct sentence: Le lo voy a decir. However, there is an important exception when the indirect object pronoun is in the third person, which brings us directly to the error in our original phrase.
The Pronoun Le to Se Transformation
Why Does Le Change to Se?
Spanish has a phonetic rule that states when an indirect object pronoun in the third person (le or les) appears immediately before a direct object pronoun beginning with the letter L (lo, la, los, las), the indirect object pronoun changes to se.
This rule exists to avoid the awkward sound of having two L sounds in succession: le lo, le la, le los, le las. The transformation to se creates a more phonetically pleasing combination.
So when you want to say I am going to tell it to him, the correct formation is:
Original: le + lo
After transformation: se + lo
Complete sentence: Se lo voy a decir
This is exactly what many learners mistakenly write as Se lo voy decir. Now let us examine what makes this form incorrect.
The Critical Error in Se lo voy decir
Where Is the Mistake?
The error in Se lo voy decir lies not with the pronoun combination itself, but with the placement of the pronouns relative to the verb construction. The phrase contains the correct pronoun pair se lo, but places them in the wrong position within the sentence structure.
When you use a conjugated verb followed by an infinitive verb (like voy followed by decir), the pronouns must attach to the infinitive, not to the conjugated verb.
In the phrase voy a decir (I am going to tell), voy is the conjugated verb and decir is the infinitive. The pronouns se and lo must attach to decir, not to voy.
Therefore, the correct construction is: Voy a decirle lo, which transforms to Voy a decírselo when the pronouns are properly attached to the infinitive.
Understanding Pronoun Attachment to Infinitives
Spanish has strict rules about when pronouns attach directly to verbs versus when they precede verbs. With infinitive verbs, gerunds, and affirmative imperative forms, pronouns must attach directly to the end of the verb as suffixes.
When you see a verb construction like voy a decir, the infinitive decir is the verb form that will receive the pronouns. The conjugated verb voy remains separate.
The pronouns attach to create: decirle lo, which then becomes decírselo after the se lo transformation.
The complete correct sentence is therefore: Voy a decírselo, which means I am going to tell it to him.
Common Variations and How to Get Them Right
Present Tense with Infinitive
When expressing future intention with the present tense of ir plus an infinitive, always attach pronouns to the infinitive:
Incorrect: Se lo voy a decir
Correct: Voy a decírselo
Other examples with voy a:
Voy a dártelo (I am going to give it to you)
Vamos a mostrarles las fotos (We are going to show them the photos)
Va a comprársela (He is going to buy it for her)
Other Modal Verbs with Infinitives
The same rule applies to other modal verbs like poder, querer, deber, and necesitar:
Puedo decírselo (I can tell it to him)
Queremos mostrárselo (We want to show it to him)
Deben entregársela mañana (They must hand it over to her tomorrow)
Necesito dárselo (I need to give it to him)
In all these cases, the pronouns attach to the infinitive verb form, not to the modal verb.
Progressive Tenses with Gerunds
When using progressive tenses with a gerund (the -ando or -iendo form), pronouns also attach to the gerund:
Estoy diciéndoselo (I am telling it to him)
Están mostrándonos las fotos (They are showing us the photos)
Voy diciéndoselo poco a poco (I am telling it to him little by little)
Notice that when pronouns attach to a gerund, you often need to add an accent mark to maintain the original stress pattern of the word.
When Pronouns Precede the Verb Instead
Conjugated Verbs in Present and Past Tenses
With fully conjugated verbs in the present, past, or other simple tenses (not followed by an infinitive), pronouns precede the verb rather than attaching to it:
Se lo digo (I tell it to him)
Se lo dije (I told it to him)
Se lo decía (I was telling it to him)
Se lo dirá (He will tell it to him)
This is the opposite pattern from infinitives and gerunds. With conjugated verbs standing alone, pronouns come before the verb.
Negative Commands
In negative commands (telling someone not to do something), pronouns also precede the verb:
No se lo digas (Do not tell it to him)
No se la muestren (Do not show it to her)
No me lo des (Do not give it to me)
Practical Examples to Clarify the Rules
The Same Meaning, Different Constructions
Let us examine how the same basic meaning changes with different grammatical structures:
With conjugated verb: Se lo digo todos los días (I tell it to him every day)
With infinitive after ir: Voy a decírselo mañana (I am going to tell it to him tomorrow)
With gerund: Estoy diciéndoselo ahora (I am telling it to him now)
With negative command: No se lo digas (Do not tell it to him)
Each construction has a different pronoun placement pattern, but they all express related ideas about the action of telling something to someone.
Building Complex Sentences
As you become more advanced, you will encounter sentences that combine multiple elements. Always remember: if you have an infinitive or gerund, pronouns attach to it; if you have a conjugated verb standing alone, pronouns precede it.
Quiero decírselo, pero no puedo encontrarlo (I want to tell it to him, but I cannot find him)
Mientras estoy diciéndoselo, él sonríe (While I am telling it to him, he smiles)
Aunque se lo dije ayer, parece que no lo recuerda (Although I told it to him yesterday, it seems he does not remember it)
Common Mistakes to Avoid
Mixing Patterns
The most frequent error learners make is mixing the attachment pattern with the preceding pattern. Once you recognize whether you are using a conjugated verb or an infinitive or gerund, the correct pronoun placement becomes automatic.
Incorrect: Se lo voy decir (mixing conjugated voy with infinitive decir)
Incorrect: Se lo estoy decir (mixing conjugated estoy with infinitive decir)
Incorrect: Digo se lo (wrong order with conjugated verb)
Each of these represents a failure to maintain consistency with the grammatical structure being used.
Forgetting the Se Lo Transformation
Another common mistake is forgetting that le becomes se when followed by a direct object pronoun beginning with L. Some learners write le lo instead of se lo, which sounds incorrect to native ears:
Incorrect: Le lo voy a decir
Correct: Voy a decírselo
Conclusion
The mistake in Se lo voy decir represents a fundamental misunderstanding of how Spanish handles pronoun placement with different verb forms. While the pronoun combination se lo is correct, its placement in this construction is wrong. The correct form is Voy a decírselo, where both pronouns attach to the infinitive verb. Understanding this distinction requires recognizing whether your verb is a conjugated form standing alone or an infinitive or gerund. With conjugated verbs, pronouns precede; with infinitives and gerunds, pronouns attach. Master this principle, and you will avoid this common error while developing a deeper, more accurate command of Spanish grammar overall. Practice these patterns consistently, and soon the correct structures will feel natural in your Spanish communication.
