Spelling and Spanish-English cognates

Some spelling errors that might stun teachers are words like *acecino, *silensio, *comunicion, …
While the fact that they write s instead of c (and vice versa) is easy to understand—since these two letters sound the same—what can be surprising is that they do it with words that are very similar in English? If a student can write silence, why do they write silensio, and not silencio, with the same consonants? Also surprising can be the shortening of long words, since for a teacher the connection between the English word and the Spanish counterpart is so obvious:
               com – mu – ni – ca - tion
                co   – mu – ni – ca – ción
Of course, there are some differences, but the syllables are basically the same.
However, the connection between the two languages is not always made by simultaneous bilinguals. In addition, the connections that are made are more holistic and based on meaning, not form. It is not that they do not know that silence translate as silencio, but this connection is not present when writing. This would not be an unlikely scenario:
    Teacher:     - Silencio, por favor.
     Student 1:  - What did she say?
    Student 2:   - She told us to be quiet.

A student who wants to write asesino might have the word murderer closer to it in mind than assassin. (In fact, the words asesino and assassin, while having the same Arabic origin, they have different uses in the present).    
In fact, this is just an example of the natural connection that speakers have of their language. At first, we see language for their meaning and communication power. We do not pay attention to formal properties. School literacy activities, while strengthening the ability to create meaning, also shift the students’ attention to the formal aspects (how words are written, grammar, etc.). For students who grow up bilingual, the same applies to both languages and the connections between them. That might surprise learners of Spanish or English as a second language. When we learned that second language as adults / young adults, we made connections with the first language we spoke.  English speakers who learn the word “simpático” in Spanish might connect it with the now English word “simpatico” (even tough is not as common as “nice”).  Spanish speakers who see “assassin” will relate it to “asesino.”   In fact, some focus on Second/Foreign language classes is to notice the difference in meaning between cognate pairs, since a second/foreign language learner might assume that if they look similar, they mean exactly the same.    
One activity that I do in the Spanish for Heritage Speakers classroom to strengthen the connection between Spanish-English words, so that students can benefit from the spelling similarities, is to ask students to find a similar word—even if the meaning is slightly different. These are some of these words:
From Spanish to English:
asesino                        silencio                        mansión                     
artificial                        cerebral                       explosión                     
horizontal                    grave                           edificio

From English to Spanish:
religious                      insect                          adherence
palace                         ceramics                     television
alcohol                        grace                           hospital                   
 
It is obvious that English grave and Spanish grave are not exactly the same; and that the word edifice is not very common; however, the goal of this activity is not to work on meaning but on formal properties. The ultimate goal is to use students’ knowledge of English spelling to facilitate Spanish spelling. 

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