Islam is probably the fastest growing religion in the world.
Statistics vary widely but even a conservative estimate from the U.S. Center for World Mission [GP1997] places its growth rate at 2.9% from 1970 to 1996, just above Christianity at 2.3%.
According to the BBC [B2005] this growth this largely a result of higher birth rates in Islamic nations and immigration to the West.
Of these, about 12.2% live in North Africa, making up 89.6% of the population there. 
Originally this area was largely animistic. Islam was first introduced with the military conquests of the Umayyad caliphate in the later half of the 7th century. At first, only the coastal areas where affected. However, as time progressed, Arabic merchants set up trade routes throughout the inland areas, bringing the message of Islam with them.
Most of the North Africans submitted  to Islam. One significant group that did not was the Copts in Egypt who were already Christian.
During the period of European colonialism, these countries where all colonized by various European countries (mostly France). The Europeans made various attempts at converting the Africans, but as current demographics show, they were largely unsuccessful.
African culture has always been one of the prototypical examples of high-context cultures. (Edward Hall).
Human Nature: Mixed
Man-Nature relationship: Man subordinate to Nature
Social Relations: Collective [HP2004]
Hofstede [GF2009] does not have statistics for North Africa. The closest would be West Africa which has the following values (from 0-100)
Power Distance: 82
Uncertainty Avoidance: 60
Long-Term Orientation: 22
In recent centuries, Westerners have often maintained a relatively large distinction between religion and society. Religion has been relegated to the position of personal opinion and is generally not considered to be something that should restrict one’s public standing. However, this is not so true in other parts of the world.
In the Arabic countries of North and West Africa, the issue of religion and culture are much more deeply related. To them, religion is not merely a matter of intellectual opinion. In fact, intellectual beliefs and convictions may have little to do with it. Instead, religion is something that defines one's cultural identity.
As a result, Muslims who adopt Christian beliefs are often faced with difficult choices. To call themselves “Christian” means to reject their society, while denying their “Christian” identity hinders potential relationships with others Christians. Because of this Christian believers in Muslim societies have taken on different identities depending on their situations. Some have opted to remain within their own culture, drawing a fine line between contextualization and syncretism of their faith. Some have broken away and adopted Western culture and habits. Most of them fall somewhere in between.
In order to understand religion and how to affect religious change in this area, it is important to understand what religion means to the people themselves. From a Western perspective it is easy to fall into the trap of thinking that religion is merely a set of beliefs and rules. This is especially true for those from a Protestant background.
In many ways the current view of religion in the West can be linked to the Protestant Reformation. One of the common phrases from the Reformation was called the Five Solas: Sola Scriptura, Solus Christus, Sola Gratia, Sola Fide, Sola Dei Gloria . The importance of this is that it lacks any reference to the community of believers (i.e. the church).
The merits of Protestant or Roman Catholic theology are not to be discussed here. What is important is that if Christian workers are to have any chance in effecting change among the hearts of these people, it must come to the people on their own terms. As Smith outlined in his book, change requires several things. Agents of change must reinforce the group's traditions and change must fit within he existing cultural patterns. [DS1984]
Religion as Part of a Cultural Identity
Among North and West Africa, the people’s religious identity is influenced strongly by their cultural identity and their cultural history. In addition, the people there have a significant colonial history as well [MN2007]. During the 15th and 19th centuries, the countries there where all colonized by the Europeans, most of whom called themselves Christian. As a result, many Africans perceive Christianity as a foreign, European religion, and Islam as their own religion.
“[The taxi cab driver] nodded for a while and then whispered, as if talking only to himself, “God is greater! But he does not speak French!” Dominated by the Christian French for decades, and having no native Christians, many of the Moroccans thought that every Christian was French, much as some people thing that every Muslim is Arab.” [SK2007]
The Importance of Language
The significance of the Arabic language to the Muslim people is another thing that may be difficult for those from a Western background to understand. No one in these days would think about speaking about the “Christian Language.”  Arabic, on the other hand, is very much the language of Islam, and in many ways it is an important part of the religion. In some cases it even goes so far as to be used as the identifying mark for a Muslim. Sonia Khūrī lived as a Christian among Muslims in West Africa, but was considered by many to be a Muslim because he spoke Arabic as his mother tongue. [SK2007]
Again, the power of language, or at least, the perception of language, is a force that is foreign to most in the West. In the case of Islam, it is not merely an issue of language, but of written language. Indeed, the name People of the Book is no accident. A Muslim prophet is someone who brings a written message from God (e.g. Moses brought the Tawrat; Jesus, the Injil; and Mohammed, the Qu’ran). To the illiterate tribes of Africa during the time of the Muslim conquests, the written language would have been a powerful thing.
Like any language, Arabic carries with it a unique style, [MN2007] and because it is used for all religious aspects, the speakers develop certain expectations of what religious language is like. When presented with religious text in another language, they seem weird or awkward.
Al-Amin bin Ali al-Mazrui, a Muslim Swahili scholar, spoke up on the importance of Arabic to Islam. According to him, the study of Arabic is a necessity for every Muslim. His belief was that Arabic is “the language of Islam because Allah choose it to reveal the Qu’ran. There is no other way to understand the Qu’ran but through the understanding of Arabic.” [GC1991] 
Diversion from Orthodox Islam
In the end, the requirements to becoming a Muslim are few and small. In general, new comers are required to recite the creed: “There is no God but Allah, and Mohammad is His prophet,” but that is about as far as it goes. Calasso notes this phenomenon:
In all the other cases recorded by Ibn Sa’d, the learning of rituals, proper behavior, and the Qu’ran, always happens during the time following conversion, or better yet, following the “entrance into Islam.” [GC2001] 
In contrast, the Christian approach implies a confession to a certain set of beliefs and implies that a believer already has the foundational knowledge for his or her faith. Because of this, Islam has been much more vulnerable to syncretism.
The original Arabic missionaries (usually either invaders or merchants), brought the message of Islam to groups of people who were largely animistic. The new religious systems did not so much replace the old one as it added a second layer of religion on top. Calasso cites Fisher, saying:
I do not think that conversion ... has occurred very often in the Islamic history of sub-Saharan Africa ... What has been much more common, in the early stages of Islamic development in any particular area, has been adhesion, as local people, still primary loyal to their ancestors, begin to add a little from Muslim faith and practice, “useful supplements” and “valuable safeguards”. [GC2001]
As a result, the beliefs of these African Muslims are not always in line with the orthodox Muslim beliefs in the Middle East. To this end, missionaries from more orthodox Arabic nations have sometimes been sent out to “reform” the natives. However, the Islamic missionaries seem to have as much difficulty as the Christians ones when it comes to Muslims.
Sonia Khūrī, a Lebanese Christian and anthropologist once noted this while he was living in Magburaka in Sierra Leone. In his book An Invitation to Laughter, he describes the result of some Egyptian Muslim scholars who come there as missionaries. In this text Alimami Suri is a native Temne trying to explain the their local customs and beliefs to the Egyptians.
None of the Alimami Suri’s emphatic assertions about Temne Islam met the approval of the head of the Egyptian mission. Christians or Muslims, missionaries shared similar attitudes towards the natives: “We know better.” I later learned that the mission stayed for nine months in Magburaka and then returned to Egypt. They were replaced by another team of four, who stayed for two more years, and then the whole program was scrapped. It proved to be counterproductive, creating more apathy than empathy. [SK2007]
The Problem of “Conversion”
Problem as a Western Idea
Part of the difficulty when talking about converting others to Christianity is that the idea of “conversion” involves a rather uniquely Western view of religion. When we think of prototypical examples of conversion, cases like Paul and his “Damascus experience” (Acts 9) come to mind. A long with conversion is the implication that there is a giving up of certain beliefs in favor of other ones.
Becoming a Muslim
As it was mentioned earlier, the process of becoming a Muslim was in some ways more of a “submission” than a “conversion”. In Arabic, the two words are not actually distinguished. Calasso cites Bulliet to explain this.
The language (Arabic) does not allow the reader to disentangle the meaning « surrender » and « convert ». This raises the question as to whether these meanings were actually separated in the minds of the actors. After all the notion of religious conversion as a moral or spiritual act that could be taken independently of other political or social action may not have been widespread in seventh-century Arabia. [GC2001]
Later on, he continues, highlighting the why it is problematic to look at “becoming muslim” as the same as converting religions.
“In a sense, a convert first became a member of the Muslim community and later discovered, or tried to discover what it meant to be a Muslim. This is why the personal conversion stories that have been preserved say so little about preaching, studying, or intellectual or moral transformation.” [GC2001]
Christians in a Muslim society
Bearing all of this in mind, how can a Christian worker have an impact in the religious domain of an Islamic society. First and foremost, the Christians must be able to communicate effectively in a way that speaks to the hearts of the other people around. One of the examples where this is a problem is the Arabic Bible. Cragg explains the problem in the following words:
It has often been observed from within Arab Islam that these do not read congenially. The reason is not simply the distinctive themes of Christian faith nor the overall shape of the New Testament with its fourfold Gospels and its church “correspondence.” It has also to do with the strange quality of the text when registered by readers whose sense of the scriptural in Arabic is made by the Qur’an. The style, the idiom, the grammar, and the syntax all convey an impression that puzzles, if it does not altogether deter, the Muslim Arab. [KC1991]
When the German Bible was first translated into Low German, it received poor reception. Some thought it was a nice idea, but could not bring themselves to read it because the style did not feel proper. Others felt strongly the translation should have never been done, that it was disrespectful to use the language of Low German in the Christian Scriptures. In the same way, Arabic speakers approach the Arabic Bible. Although it is Arabic, it is based on styles from writers in different languages and does not fit within the style of Arabic religious writing.
Even things as simple as a different name for God can be a difficult. The Muslim believes very strongly that there is one God named Allah. To them, the other names are all false gods and idol. As a result, many Muslim Background Believers continue to use the name Allah to refer to God. “I asked a Christian Arab why he continues to use the term Allah when he prays, and he whispered to me, “I cannot bring myself to use the Hebrew names, you know?” [EC2004]
Another problem that must be handled is the issue of identity. If a Muslim becomes a Christian, can he still be called a Muslim. Are some Muslim practices still permissible. Historically, the answers to this question have been pretty harsh. For example, the Anglicans in Palestinian. Riah Abu El-Assal is an Arab who became an Anglican bishop. Although this is in Palestine and not North Africa, the issue of relating to Muslims still exists. In one of his online article, Abu El-Assal shares the following insights regarding the European domination of Europeans in the Christian climate of his own land.
Much of the cultural legacy of the French, Dutch, British, Italians, and Americans has its comical side—like convincing Arab Anglicans to observe high tea at four Greenwich Mean Time! But, it has harmed Palestinian Christians, already adherents to a faith considered alien and aberrant by their neighbors, leaving them without control of their own church or power to implement the tenets of their faith. [AE2006]
Different people have addressed this problem in different ways. One common measure of the level of immersion is the C1–C6 scale [CM2003] which ranges from C1 (Traditional church using an outsider language) to C6 (Small Christi-centered communities of secret/underground believers. Note that in this scale, the members of the categories C4–C6 do not even call themselves “Christian.”
There is no silver bullet to missionary work among the Muslim people. However, it is important to understand the problems. Any attempt to bring about religious change will never work if the cultural considerations of the people are not kept in mind.